Sessions on sub-512K-context models were spending most of their wall-clock
re-summarizing: the 50% trigger left too little post-compaction headroom
(the incompressible floor — system prompt, tool schemas, protected tail,
rolling summary — ate most of the reclaimed space), so compaction re-fired
every 1-2 turns. Three compounding defects fixed:
- Threshold floor: models with context windows below 512K now trigger at
>=75% of the window (raise-only — a higher configured value or per-model
autoraise like Codex gpt-5.5's 85% always wins). Re-derived on
update_model() in both directions.
- No max_tokens on the summary call: the summary budget is prompt guidance
only ("Target ~N tokens"). The wire cap truncated summaries mid-section
on the Anthropic Messages / NVIDIA NIM paths (thinking models burn the
cap on reasoning first), yielding truncated or thinking-only summaries
and compaction loops. Summary token ceiling lowered 12K -> 10K to keep
the guidance within the intended 1K-10K envelope.
- Reasoning traces excluded end-to-end: inline <think>/<reasoning> blocks
are now stripped from assistant content before serialization to the
summarizer, and from the summarizer's own output before the summary is
stored (previously a thinking summarizer model's trace was persisted in
_previous_summary and re-fed into every iterative update, compounding
bloat). Native reasoning fields were already excluded.
Verified E2E with real imports against a temp HERMES_HOME: threshold table
across 64K-1M windows, override interactions (user 0.85 wins, spark 0.70
raised, gpt-5.5 0.85 kept), full compress() round-trip with a thinking
summarizer, and wire-kwargs capture proving no max_tokens is sent.
Compression could produce a transcript with ZERO user-role messages,
which OpenAI-compatible backends (vLLM/Qwen) reject with a non-retryable
`400 No user query found in messages`. This crashes `hermes kanban`
workers unrecoverably: every resume replays the same poisoned history and
fails on the very first request after a successful compaction.
The existing #52160 guard pins the handoff summary to role="user" only
when `last_head_role == "system"` — i.e. when the system prompt sits
inside `messages` (the gateway `/compress` path). The main
auto-compression path prepends the system prompt at request-build time,
so the list handed to `compress()` starts with a user/assistant turn,
`last_head_role` defaults to "user", and the summary is emitted as
role="assistant". A kanban worker seeded with a single short
`"work kanban task <id>"` prompt followed by nothing but assistant/tool
turns therefore ends up user-less once that early turn is summarised.
Generalise the guard: when no user-role message survives in the protected
head or the preserved tail, force the summary to carry role="user" so the
request always has at least one user turn. When a user does survive
(e.g. in the tail), the guard does not fire, so alternation is preserved.
Fixes#58753.
Follow-up to the per-site strips from the review gate. The two copy-site
strips are correct but positional — a copy site added after the assembly
loops would re-leak _db_persisted into the child-session flush. Add a single
terminal sweep (_strip_persistence_markers) run once on the fully-assembled
compressed list so the invariant 'no compacted message leaves compress()
carrying a persistence marker' is structural, not dependent on copy-site order.
- agent/context_compressor.py: _strip_persistence_markers() called before
compress() returns; helper docstring notes the sweep is the authoritative guard
- tests/agent/test_context_compressor.py: structural regression — neuter the
per-site helper to a leaking copy, assert the terminal sweep still strips
- tests/run_agent/test_compression_persistence.py: pin the fixture assumption
behind the exact-equality row-count assertion
Shallow messages[i].copy() during context compression propagated the
_db_persisted marker from cached gateway incremental flushes into the
post-rotation compressed list. _flush_messages_to_session_db then skipped
every row when writing to the new child session, so gateway restarts
lost the compacted transcript (severe amnesia).
Strip the marker in _fresh_compaction_message_copy() and add regression
tests for rotation flush + compressor assembly.
Fixes#57491
Follow-up to the END-MARKER reorder: moving the summary prefix after the
[PRIOR CONTEXT] wrapper meant _is_context_summary_content (prefix-at-start)
no longer recognized a merged-tail summary. That silently broke three
consumers — the last-real-user anchor (would pick the merged summary as a
real user turn, causing active-task loss), the carry-forward summary find,
and the auto-focus skip. _strip_summary_prefix would also carry the wrapper
+ stale tail content forward as the next summary body.
Extract the two delimiter strings into _MERGED_PRIOR_CONTEXT_HEADER /
_MERGED_SUMMARY_DELIMITER constants (writer + detector stay in sync), teach
_is_context_summary_content and _strip_summary_prefix to look past the
delimiter, and add a regression test. Standalone summaries unchanged.
When the compression summary is merged into the first tail message
(the alternation corner case where a standalone summary role would
collide with both head and tail), the old format was
SUMMARY + END_MARKER + OLD_TAIL_CONTENT — so the preserved tail content
appeared AFTER the end marker and the model could read it as a fresh
message to respond to.
Reorder so the END MARKER is always last: old tail content is wrapped in
[PRIOR CONTEXT ...][END OF PRIOR CONTEXT — COMPACTION SUMMARY BELOW]
delimiters, then the summary, then the END MARKER. _append_text_to_content
handles both string and multimodal-list content.
Salvaged from #56372 by @Gromykoss. Only the END-MARKER reorder half is
carried over. The PR's second change (a post-compaction pass that strips
user-role messages before the first summary marker on compression_count>=2)
was dropped: on 2nd+ compactions the protected head decays to system-only
(_effective_protect_first_n -> 0, #11996) so the targeted 'ghost head user'
does not occur, and where the strip does fire it deletes legitimate recent
tail user turns (data loss) and can leave consecutive assistant messages
(role-alternation violation).
The original cross-session contamination fix (#38788) only cleared
_previous_summary in on_session_end(), but on_session_reset() clears
14+ per-session variables. When a session ends (cron exit, gateway
expiry, session-id rotation) and the compressor instance is reused,
the surviving stale state causes:
- _ineffective_compression_count surviving → next session skips
compression prematurely (anti-thrashing guard misfires)
- _summary_failure_cooldown_until surviving → next session blocks
summary generation for an unrelated transient error
- _last_compress_aborted surviving → callers think compression is
still aborted
- _last_aux_model_failure_* surviving → stale error warnings shown
- _last_summary_dropped_count / _last_summary_fallback_used
surviving → misleading user warnings
- _context_probed / _context_probe_persistable surviving → stale
context-probe state
Also fix on_session_reset() which was missing _last_compress_aborted
clearing — a /new or /reset would inherit the aborted flag from the
prior conversation.
Add 6 targeted tests covering the leak vectors and a parity test
ensuring on_session_end and on_session_reset always clear the same
surface.
After the first compaction protect_first_n decays, so on a later compaction
the only protected head message can be the system prompt. Adapters like
Anthropic and Bedrock send the system prompt as a separate parameter, so the
summary becomes the first message in messages[] — and Anthropic rejects any
request whose first message is not role=user (HTTP 400). Pin the summary to
role=user when the head is system-only, and stop the collision-flip logic from
reverting it back to assistant.
Salvaged from #52167.
Co-authored-by: liuhao1024 <sunsky.lau@gmail.com>
compress() eagerly reset _last_summary_auth_failure and
_last_summary_network_failure at the top of every call. On a second
compress() during the failure cooldown, _generate_summary() returns None from
the cooldown early-return WITHOUT re-asserting those flags, so the abort guard
saw False and fell through to the destructive static-fallback that drops the
middle window — the data-loss #29559/#25585 describe. Stop resetting them
eagerly; a successful summary already clears both, so letting them persist
across calls is safe and keeps the cooldown abort protection intact.
Salvaged from #52056.
Co-authored-by: srojk34 <286497132+srojk34@users.noreply.github.com>
_sanitize_tool_pairs inserted stub role="tool" results for orphaned
tool_calls. The pre-API repair_message_sequence() tracks known call IDs by
tc.get("id") while this sanitizer keys on call_id||id; when they disagree
(Codex Responses API: id != call_id) the stubs are silently dropped by the
repair pass, re-exposing the original orphans. Strip the orphaned tool_calls
at the source instead (preserving any text content, adding a placeholder for
an otherwise-empty assistant turn) to avoid the mismatch class entirely.
Salvaged from #51225.
Co-authored-by: liuhao1024 <sunsky.lau@gmail.com>
A context-compaction handoff banner is inserted with role="user" when the
protected head ends in an assistant/tool message. On a resumed or
multi-compaction session, _find_last_user_message_idx would return that
banner as the latest user turn, so _ensure_last_user_message_in_tail anchored
the tail to the summary and rolled the genuine last user message into the
next compaction — the exact active-task loss the anchor exists to prevent
(#10896/#22523).
Reuse the existing _is_context_summary_content helper to skip summary banners
when locating the last real user message.
Salvaged from #36626 by Frank Song (issue #36624). The PR's other two changes
(demoting completed tool results inside the protected tail; a preflight
compression_exhausted result) are superseded on current main by the min_tail
floor (#39170), the no-op compression counting (#40803), and the existing
413/disabled terminal-error paths.
When the last user message sits exactly at head_end (the first compressible
index), _ensure_last_user_message_in_tail's final max(last_user_idx,
head_end + 1) clamp returns head_end + 1, pushing the user into the compressed
region without its assistant reply. The summariser then records it as a
pending ask, and the next session re-executes the already-completed task
(lights off twice, file deleted twice, message re-sent).
Fix: apply Causal Coupling — a compaction boundary must never split a
(user -> assistant [-> tool results]) turn-pair. Add _find_turn_pair_end and,
when the clamp would orphan the user, push the cut forward to pair_end so the
completed pair is summarised together and marked done.
8 new tests in TestTurnPairPreservation; 133 compressor tests pass.
When the summary LLM hits a 429/transient failure, _generate_summary() sets
a cooldown and returns None; compress() inserts a static fallback marker and
returns. Tokens stay above threshold, so should_compress() kept returning
True and every subsequent agent turn re-fired _compress_context() — the CLI
appeared frozen until the cooldown expired.
Add a cooldown guard to should_compress(): return False while
_summary_failure_cooldown_until is in the future. Reuses the existing float;
no new state. Manual /compress (force=True) still clears the cooldown first.
Fixes#11529
Follow-up hardening on the salvaged #54465 backoff persistence work.
The lease refresher's loop treated ANY falsy refresh as a permanent stop
(`if not refreshed: break`), conflating two distinct cases:
- genuine lost-ownership (rowcount 0) — correct to stop, and
- a one-off transient DB error (write contention that escapes
_execute_write's retry budget) — which returned False identically.
A single transient blip therefore killed the lease for the rest of a
multi-minute compression call, silently reintroducing the exact 300s-TTL <
~361s-call expiry wedge the PR set out to fix.
Changes:
- _CompressionLockLeaseRefresher._run now tolerates a bounded run of
consecutive failures (_MAX_CONSECUTIVE_REFRESH_FAILURES = 3) before giving
up the lease; a recovered tick resets the counter. Worst-case extra hold is
cap * refresh_interval, still bounded by the acquirer's TTL.
- Replace the two remaining silent `except Exception: pass` arms in the
compression-failure-cooldown persist/clear helpers with debug logging, for
parity with their sqlite3.Error sibling arms (a non-sqlite bug was invisible).
- Document the join(timeout=1.0) quiesce bound in stop().
- Add 3 regression tests: single-blip tolerance, persistent-failure stop at the
cap, and refresh-raising tolerance.
Add compression.minimum_context_floor config key that allows users
to lower the compression threshold floor below the hardcoded 64K
default, preventing infinite tool-call loops on models whose
structured output degrades well before 64K tokens.
- agent/model_metadata.py: add get_configurable_minimum_context()
helper with 16K hard safety limit
- agent/context_compressor.py: accept minimum_context_floor param,
thread it through _compute_threshold_tokens
- agent/conversation_compression.py: use compressor's floor for
aux model context validation
- agent/agent_init.py: read compression.minimum_context_floor from
config and pass to ContextCompressor
- gateway/run.py: cache-busting includes new key
Salvaged from #31686 by @Tranquil-Flow onto current main.
Resolves conflicts with in-place compaction (#38763) and max_tokens
threshold computation (#43547) that landed after the original PR.
Closes#31600
When context compaction's summary generation fails, the compressor's default
path (abort_on_summary_failure=False) drops the middle window and inserts a
static 'summary unavailable' marker — destroying the compacted turns. #29559
reported the field impact: a Connection error at the compaction moment dropped
124->15 messages (110 lost) for a long browser-automation task; #25585 is the
same failure mode (failed summary commits a destructive compaction anyway).
compress() already has an EXCEPTION to the historical drop default: auth
failures (401/403) ALWAYS abort and preserve the session, because rotating into
a placeholder-summary child on a broken credential strands the user. A transient
network/connection error is the same situation in reverse: it WILL recover, and
retrying then is strictly better than discarding context for a momentary blip.
Extend the always-abort carve-out to terminal connection/network failures:
- new _last_summary_network_failure flag, set in _generate_summary's terminal
failure branch when _is_connection_error(e) (reached only after any main-model
fallback is exhausted), reset alongside the auth flag;
- compress() aborts when it's set (returns messages unchanged,
_last_compress_aborted=True), independent of abort_on_summary_failure;
- a network-specific operator warning (distinct from the auth + config-flag
messages).
Scoped to connection errors only: a generic 500/400 still takes the historical
fallback-drop path (test_non_auth_failure_still_uses_fallback_path stays green).
Tests: network-failure detection + abort-despite-flag-false, both mutation-checked
(removing the flag-set fails detection; removing the carve-out fails the abort).
The compaction trigger compared estimated input against context_length *
threshold, but the provider reserves max_tokens of OUTPUT out of the same
window. With a large max_tokens (e.g. 65536 on a custom provider) the usable
input budget is materially smaller than the raw window, so sessions hit a
provider 400 before compaction ever fired.
_compute_threshold_tokens now subtracts the output reservation
(context_length - max_tokens) before applying the percentage and the
small-window 85% guard. max_tokens is stored on the compressor (threaded from
agent.max_tokens at construction) and reused across update_model() switches;
None = provider default = no reservation (full-window behavior, unchanged).
Reimplemented on the current _compute_threshold_tokens surface (the inline
threshold calc the original PR targeted was since refactored for the
small-window #14690 fix); composes with that 85% guard on the effective budget.
Credit: @kyssta-exe (#43651) — original design for the output-token
reservation in the compaction threshold.
Closes#43547.
After a compaction, the post-compression path parks last_prompt_tokens=-1 and
sets awaiting_real_usage_after_compression=True, but last_real_prompt_tokens
still holds the stale pre-compression value (above threshold). should_defer_
preflight_to_real_usage() hit the 'last_real_prompt_tokens >= threshold => False'
short-circuit and let preflight fire a SECOND compaction before the provider
reported real post-compaction usage. Add an early-return on the awaiting flag so
deferral holds for exactly one turn; update_from_response() clears it.
The flag-setting half (#36718) already landed on main via the in-place
compaction path (conversation_compression.py); this adds the missing
should_defer guard that consumes it.
Credit:
- @ashishpatel26 (#38133) — diagnosis + the should_defer early-return design
- @Tranquil-Flow (#36769) — same #36718 fix, identical guard placement
Closes#36718.
The tail-protection budget walks estimated an assistant message's tokens from content + function.arguments only, dropping each tool_call's id, type and function.name (plus JSON structure). Assistant turns that fan out into parallel tool calls were undercounted by 2-15x (a 4-tool-call turn measures ~73 vs ~1,090 real tokens), so the protected tail overshot tail_token_budget and compression ran far below its intended ratio — context kept growing.
Consolidate the three duplicated budget walks (_prune_old_tool_results and the two passes in _find_tail_cut_by_tokens) into a single _estimate_msg_budget_tokens() helper that counts the full tool_call envelope via len(str(tc)), consistent with how _estimate_message_chars estimates message size elsewhere.
Tested on Windows: new tests/agent/test_compressor_tool_call_budget.py plus the existing compression suite (test_context_compressor, compressor_image_tokens, cross_session_guard, infinite_compaction_loop) — 209 passed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
When an OpenAI-compatible proxy (e.g. cmkey.cn, one-api Anthropic channels)
returns a well-formed HTTP 200 whose summary content is null or empty/
whitespace-only, _generate_summary coerced it to "" and stored a prefix-only
summary — silently replacing the compacted turns with nothing. The model then
lost all in-progress context after compression (#11978, #11914).
_validate_llm_response already guards None / empty-choices, so those never
reach the compressor; the gap was a well-formed response with empty *content*.
Now treat empty content as a summary failure: raise so it routes through the
existing main-model fallback then transient cooldown, dropping the turns
without a summary rather than wiping context with an empty one.
Also narrow the bare 'except RuntimeError' so only genuine 'No LLM provider
configured' errors take the 600s no-provider cooldown; empty/invalid-response
RuntimeErrors from a configured provider now correctly get the main-model
fallback instead of being misrouted into the long no-provider cooldown.
Reported by @Hung2124; area identified by @annguyenNous in #39590.
The compaction threshold is max(context_length * threshold_percent,
MINIMUM_CONTEXT_LENGTH=64000). The floor prevents premature compression on
large models, but degenerates at small windows: a model at exactly 64000
ctx gets max(32000, 64000) = 64000 — a threshold equal to the ENTIRE
window. should_compress() can then never fire, because the provider
rejects the request before usage reaches 100%. Auto-compression silently
never triggers for any model whose context_length <= MINIMUM /
threshold_percent (e.g. 64K-per-slot local models).
Centralize the calc in _compute_threshold_tokens(). When the floor would
meet or exceed the context window, trigger at 85% of the window
(_MIN_CTX_TRIGGER_RATIO) — high enough that a minimum-context model uses
most of its budget before compacting (compacting at the 50% percentage
would waste half the small window), but below 100% so compaction actually
fires before the provider rejects the request. This mirrors the existing
gpt-5.5/Codex 85% autoraise rationale. Large-context behavior (floor at
64000) is unchanged; both call sites (__init__ and update_model) use the
shared helper.
Co-authored-by: soynchux <soynchuux@gmail.com>
Co-authored-by: LeonSGP43 <154585401+LeonSGP43@users.noreply.github.com>
Co-authored-by: Tranquil-Flow <tranquil_flow@protonmail.com>
ContextCompressor.update_model() recomputed context_length/threshold/budgets
but kept the cross-call calibration state (last_real_prompt_tokens,
last_rough_tokens_when_real_prompt_fit, last_compression_rough_tokens,
awaiting_real_usage_after_compression, _ineffective_compression_count) from the
PREVIOUS model.
Those fields encode 'the provider proved this prompt fit' / 'preflight can be
deferred' decisions valid only for the model that produced them. Carried across
a switch to a smaller-context model, should_defer_preflight_to_real_usage() used
the old model's 'it fit' history to SKIP a preflight compression the new model
actually needed — sending an oversized prompt the provider rejects (#23767).
update_model() now clears that state; the new model's first response repopulates
it via update_from_response(). Verified E2E: after a 200K->65,536 switch, defer
no longer suppresses and should_compress fires on an over-threshold estimate.
protect_first_n keeps the first N non-system messages verbatim through
compaction so the original task framing survives. But it was applied on
EVERY compression pass: the same early user turns were re-copied into each
child session and never summarized away, so across a long, repeatedly-
compressed session those old messages became immortal and grew the
protected head unboundedly (#11996, P1).
Decay it: protect_first_n applies on the FIRST compaction only. Once the
session has been compressed at least once (compression_count >= 1, or a
handoff summary already exists), the early turns are captured in the
summary, so _effective_protect_first_n() returns 0 and only the system
prompt stays protected. The decay is read at compress_start computation
time, before compression_count/_previous_summary are mutated at the end of
compress(), so the first pass still protects correctly.
Co-authored-by: truenorth-lj <liliangjya@gmail.com>
Co-authored-by: davidvv <david.vv@icloud.com>
When LLM summarization fails, the deterministic fallback summary rendered
the latest user ask (active_task = "User asked: '<ask>'") verbatim under
THREE headings — Historical Task Snapshot, Historical In-Progress State,
and Historical Pending User Asks. Re-presenting an already-handled ask as
unresolved in-progress/pending work made the model re-answer it AND treat
the resurrected ask as the active turn, burying the genuinely-new
post-compaction user message (#49307: answer repetition + new-instruction
loss, P1).
Keep the latest ask once, under Task Snapshot, as historical context only.
The In-Progress and Pending-Asks sections now say 'Unknown / None
recoverable from deterministic fallback' (consistent with the Active
State / Key Decisions / Resolved Questions sections) and explicitly note
the ask is historical, not outstanding. The raw turn text still appears in
the verbatim 'Last Dropped Turns' transcript — that's the dropped-turn
record, not a re-labeled instruction.
Note: the separate role=assistant standalone-summary regurgitation
(#33256) is left as-is — that role choice is constrained by strict message
alternation (user collides with a user-ending head) and is already
mitigated by the summary end-marker; forcing the role would risk the
alternation invariant.
Co-authored-by: r266-tech <r2668940489@gmail.com>
Co-authored-by: kyssta-exe <kyssta-exe@users.noreply.github.com>
Context compression is atomic, but a gateway interrupt (an incoming user
message while the agent is busy) could abort the in-flight summary call.
The Codex Responses aux stream polls the thread interrupt flag and raised
InterruptedError unconditionally — so compression fell back to a degraded
static 'summary unavailable' marker, losing the real handoff (#23975).
Add a thread-local interrupt-protection flag (aux_interrupt_protection
context manager) in auxiliary_client; the Codex stream's cancellation
check honors it. The compressor wraps its summary call_llm in the context
manager. Timeouts still fire (a hung call must die) and all other aux
tasks (vision, web_extract, title_generation, …) stay interruptible.
Re-entrant, so the main-model retry recursion is safe.
Co-authored-by: konsisumer <der@konsi.org>
When the auxiliary summary call fails with an authentication/permission
error (HTTP 401/403), context compression now ABORTS and preserves the
session unchanged instead of rotating into a child session with a
placeholder summary.
Before: a 401 (invalid/blocked key, or a token pointed at the wrong
inference host) fell through every transient-error check to 'return
None', and because compression.abort_on_summary_failure defaults False,
compress() took the static-fallback path and rotated the session anyway
(messages N->N). The user landed on a fresh-but-broken session that kept
failing the same way — paying for a full-context API call each turn with
no useful compression.
After: _generate_summary classifies 401/403 as a non-recoverable auth
failure (_last_summary_auth_failure) and compress() aborts on it
regardless of abort_on_summary_failure. A distinct auxiliary summary_model
that 401s still retries once on the main model first (its dedicated creds
may be the only broken thing); the abort only sticks when the main model
itself auth-fails or the fallback also auth-fails. The existing
_last_compress_aborted handling in conversation_compression.py already
skips rotation and emits a warning, so no session rotation occurs.
Tests: TestAuthFailureAborts — 401/403 flagging, compress() aborts despite
flag=False, non-auth failures keep the historical fallback path, and
aux-model auth failure recovers on main without aborting.
Summary messages (standalone insertion and merge-into-tail) now carry a
metadata flag so frontends (CLI, Desktop, gateway, TUI) can distinguish
them from real assistant/user messages without content-prefix heuristics.
Re-applied from PR #38434 onto current main (conflicted with the
_SUMMARY_END_MARKER hoist). Key renamed from the PR's
'is_compressed_summary' to '_compressed_summary': the wire sanitizers
strip underscore-prefixed message keys, so the flag stays in-process and
can never reach strict gateways (Fireworks/Mistral/Kimi reject unknown
keys with 'Extra inputs are not permitted').
Two-pronged fix for the WebUI "context compaction block in place of
last assistant response" regression.
Agent layer (the real fix). ``_find_tail_cut_by_tokens`` already had
``_ensure_last_user_message_in_tail`` to keep the most recent user
request out of the compressed middle (#10896), but no symmetric
anchor for the assistant side. When the conversation has an
oversized recent tool result or a long stretch of tool-call/result
pairs *after* the assistant's last visible reply, the token-budget
walk can stop with the previously-visible reply on the wrong side
of ``cut_idx``. The summariser then rolls it into the single
``[CONTEXT COMPACTION — REFERENCE ONLY]`` block persisted as
``role="user"`` or ``role="assistant"``, and from the operator's
perspective the WebUI session viewer
(``web/src/pages/SessionsPage.tsx``) and the TUI chat panel both
suddenly show the opaque "Context compaction" block in the slot
where they were just reading the actual answer:
User: "i cant see the output of the last message you sent,
i did see it previously, however now see 'context
compaction'"
Added ``_ensure_last_assistant_message_in_tail`` mirror of the
user-side anchor. It looks for the most recent assistant message
with non-empty text content (skipping tool-call-only assistant
"stubs" which the UI renders as small "calling tool X" indicators
rather than a readable bubble) and walks ``cut_idx`` back through
the standard ``_align_boundary_backward`` so we don't split a
tool_call/result group that immediately precedes it. The two
anchors are chained — each only walks ``cut_idx`` backward, so
the tail can only grow.
Falls back to "most recent assistant of any kind" only when no
content-bearing reply exists in the compressible region (fresh
multi-step tool sequence with no prior reply) — in that case the
agent-side fix is effectively a no-op and the existing
user-message anchor carries the load.
WebUI layer (clarity). Added ``isCompactionMessage`` detector that
recognises the ``[CONTEXT COMPACTION — REFERENCE ONLY]`` (current)
and ``[CONTEXT SUMMARY]:`` (legacy) prefixes from
``agent/context_compressor.py``, and a new ``compaction`` entry
in ``MessageBubble``'s ``ROLE_STYLES`` map. Compaction blocks
now render as muted, italicised system-style rows labelled
``Context handoff`` — clearly metadata, not the assistant's
actual reply — so an operator scrolling back through a long
session can't mistake the summary for a real answer.
Keeping the detected prefixes inline (rather than importing them)
because the WebUI bundle has no Python interop. A guardrail comment
points readers at the source-of-truth constants in
``agent/context_compressor.py``.
Follow-up to the #33346 cherry-pick:
- the marker string was duplicated at both insertion sites (standalone +
merged-into-tail); hoist to a module constant
- _strip_summary_prefix now also strips a trailing end marker so a
rehydrated handoff body doesn't leak the boundary directive into the
iterative-update summarizer prompt (it is re-appended on insertion)
When the compression summary lands as an assistant-role message (head ends
with user), the end marker was not appended. Models may regurgitate the
summary text as their own visible output when there's no clear boundary
signal (#33256).
The end marker was already appended for user-role summaries (#11475, #14521)
but the assistant-role path was missed in the original fix. This ensures ALL
standalone summary messages carry the boundary marker, preventing summary
text from leaking into user-visible chat output.
Legibility pass on the consolidated prefix: collapse the topic-overlap rule
from three overlapping sentences into one WINS sentence + one discard/no-wrap-up
sentence (same constraints, less dilution), fix the module docstring to
describe the headings that actually shipped, and correct the #10896 comment's
heading name (Historical Pending User Asks).
The prompt consolidation above retires the carveout-era prefix. Without a
frozen copy in _HISTORICAL_SUMMARY_PREFIXES, summaries persisted by
pre-upgrade builds would lose detection (_is_context_summary_content) and
renormalization (_strip_summary_prefix) — the exact regression class the
tuple exists to prevent. Adds contract tests covering every frozen prefix.
Refs #41607#38364#42812
ContextCompressor inherited a no-op on_session_end() from ContextEngine, so
per-session iterative-summary state (_previous_summary) survived a real session
boundary on a reused compressor instance. Override it to clear the summary the
moment the owning session ends, complementing the point-of-use guard in
compress(). Closes the cross-session contamination path in #38788.
Co-authored-by: dusterbloom <32869278+dusterbloom@users.noreply.github.com>
When a cron or background session compacts, it sets _previous_summary for
iterative updates. If that session ends without /new or /reset (which calls
on_session_reset()), the stale summary survives on the ContextCompressor
instance. A subsequent live messaging session's compaction then injects it as
'PREVIOUS SUMMARY:' into the summarizer prompt — contaminating the live
session with unrelated content from the prior session.
Add an else guard in compress(): when no handoff summary is found in the
current messages but _previous_summary is non-empty, discard it so
_generate_summary() starts fresh instead of iteratively updating a stale
cross-session summary.
Fixes#38788
When summary_target_ratio is large (e.g. 0.45) and the context_length is
moderate (e.g. 96000), the soft_ceiling (token_budget * 1.5) can exceed
the total transcript size. _find_tail_cut_by_tokens walks the entire
transcript without breaking early, and the resulting compress window is
either empty (compress_start >= compress_end) or a single message whose
summary-of-one overhead saves ~0 tokens.
Both outcomes cause a no-op compression that does not increment
_ineffective_compression_count, so should_compress() returns True on
every subsequent turn and the loop repeats endlessly.
Fix (two layers):
1. _find_tail_cut_by_tokens: when the backward walk consumed the entire
transcript without breaking (cut_idx <= head_end and accumulated <=
soft_ceiling), re-walk with the raw (non-inflated) token budget to
find a meaningful cut that gives the summarizer a useful middle window.
2. compress(): when compress_start >= compress_end, increment
_ineffective_compression_count and log a warning so the existing
anti-thrashing guard in should_compress() can break the loop.
Fixes#40803
Compaction summaries now receive the current date and instruct the
summarizer to rewrite completed actions as absolute, dated, past-tense
facts (e.g. "email John about the proposal" -> "Sent the proposal email
to John on 2026-06-07"). A resumed conversation no longer re-issues work
that already happened or treats a finished action as still pending.
The date is resolved via hermes_time.now() (date-only, user-configured
timezone) inside _generate_summary. The compaction summary is a
mid-conversation message that is never part of the cached prefix, so the
date does not affect prompt-cache stability. Date resolution is
best-effort: a clock failure omits the rule rather than blocking
compaction. The rule rides the shared template, so both first-compaction
and iterative-update prompts carry it.
Inspired by Poke's summarization (temporal anchoring + semantic
preservation).
A handoff persisted under an older SUMMARY_PREFIX can be inherited into a
resumed lineage. _strip_summary_prefix only matched the current/legacy
literal, so on re-compaction the old 'resume exactly from Active Task'
directive stayed embedded in the body and kept hijacking replies to new,
unrelated user messages.
- Add _HISTORICAL_SUMMARY_PREFIXES (pre-#35344 prefix) and strip/recognize
them in _strip_summary_prefix + _is_context_summary_content so resumed
stale handoffs are re-normalized to the current latest-message-wins prefix.
- Reconcile the overlapping Active Task template edits from the salvaged
#26290 (reverse-signal cancellation) and #32787 (capture open questions /
decisions, don't write None too eagerly) — both intents kept.
- Regression coverage in tests/agent/test_resume_stale_active_task.py.
- AUTHOR_MAP entries for both salvaged contributors.
