Closes#8933 more fully, extending the per-tool transform_terminal_output
hook from #12929 to a generic seam that fires after every tool dispatch.
Plugins can rewrite any tool's result string (normalize formats, redact
fields, summarize verbose output) without wrapping individual tools.
Changes
- hermes_cli/plugins.py: add "transform_tool_result" to VALID_HOOKS
- model_tools.py: invoke the hook in handle_function_call after
post_tool_call (which remains observational); first valid str return
replaces the result; fail-open
- tests/test_transform_tool_result_hook.py: 9 new tests covering no-op,
None return, non-string return, first-match wins, kwargs, hook
exception fallback, post_tool_call observation invariant, ordering
vs post_tool_call, and an end-to-end real-plugin integration
- tests/hermes_cli/test_plugins.py: assert new hook in VALID_HOOKS
- tests/test_model_tools.py: extend the hook-call-sequence assertion
to include the new hook
Design
- transform_tool_result runs AFTER post_tool_call so observers always
see the original (untransformed) result. This keeps post_tool_call's
observational contract.
- transform_terminal_output (from #12929) still runs earlier, inside
terminal_tool, so plugins can canonicalize BEFORE the 50k truncation
drops middle content. Both hooks coexist; they target different layers.
Expands the plugin interface so slash command handlers can dispatch tool
calls through the registry with parent agent context wired up automatically.
This is the public API for plugins that need to orchestrate tools like
delegate_task — they call ctx.dispatch_tool() instead of reaching into
framework internals. The parent agent is resolved lazily from _cli_ref
when available (CLI mode) and omitted in gateway mode (tools degrade
gracefully).
Enables the hermes-deliver-plugin pattern where /deliver and /fanout
slash commands spawn subagents via delegate_task without touching the
agent conversation loop.
7 new tests covering: registry delegation, parent_agent injection from
cli_ref, gateway mode (no cli_ref), uninitialized agent, explicit
parent_agent override, kwargs forwarding, return value passthrough.
Complete the half-built plugin slash command system. The dispatch
code in cli.py and gateway/run.py already called
get_plugin_command_handler() but the registration side was never
implemented.
Changes:
- Add register_command() to PluginContext — stores handler,
description, and plugin name; normalizes names; rejects conflicts
with built-in commands
- Add _plugin_commands dict to PluginManager
- Add commands_registered tracking on LoadedPlugin
- Add get_plugin_command_handler() and get_plugin_commands()
module-level convenience functions
- Fix commands.py to use actual plugin description in Telegram
bot menu (was hardcoded 'Plugin command')
- Add plugin commands to SlashCommandCompleter autocomplete
- Show command count in /plugins display
- 12 new tests covering registration, conflict detection,
normalization, handler dispatch, and introspection
Closes#10495
Add ctx.register_skill() API so plugins can ship SKILL.md files under
a 'plugin:skill' namespace, preventing name collisions with built-in
Hermes skills. skill_view() detects the ':' separator and routes to
the plugin registry while bare names continue through the existing
flat-tree scan unchanged.
Key additions:
- agent/skill_utils: parse_qualified_name(), is_valid_namespace()
- hermes_cli/plugins: PluginContext.register_skill(), PluginManager
skill registry (find/list/remove)
- tools/skills_tool: qualified name dispatch in skill_view(),
_serve_plugin_skill() with full guards (disabled, platform,
injection scan), bundle context banner with sibling listing,
stale registry self-heal
- Hoisted _INJECTION_PATTERNS to module level (dedup)
- Updated skill_view schema description
Based on PR #9334 by N0nb0at. Lean P1 salvage — omits autogen shim
(P2) for a simpler first merge.
Closes#8422
Plugins can now return {"action": "block", "message": "reason"} from
their pre_tool_call hook to prevent a tool from executing. The error
message is returned to the model as a tool result so it can adjust.
Covers both execution paths: handle_function_call (model_tools.py) and
agent-level tools (run_agent.py _invoke_tool + sequential/concurrent).
Blocked tools skip all side effects (counter resets, checkpoints,
callbacks, read-loop tracker).
Adds skip_pre_tool_call_hook flag to avoid double-firing the hook when
run_agent.py already checked and then calls handle_function_call.
Salvaged from PR #5385 (gianfrancopiana) and PR #4610 (oredsecurity).
- PluginContext.register_context_engine() lets plugins replace the
built-in ContextCompressor with a custom ContextEngine implementation
- PluginManager stores the registered engine; only one allowed
- run_agent.py checks for a plugin engine at init before falling back
to the default ContextCompressor
- reset_session_state() now calls engine.on_session_reset() instead of
poking internal attributes directly
- ContextCompressor.on_session_reset() handles its own internals
(_context_probed, _previous_summary, etc.)
- 19 new tests covering ABC contract, defaults, plugin slot registration,
rejection of duplicates/non-engines, and compressor reset behavior
- All 34 existing compressor tests pass unchanged
Plugins can now subscribe to session boundary events via
ctx.register_hook('on_session_finalize', ...) and
ctx.register_hook('on_session_reset', ...).
on_session_finalize — fires during CLI exit (/quit, Ctrl-C) and
before /new or /reset, giving plugins a chance to flush or clean up.
on_session_reset — fires after a new session is created via
/new or /reset, so plugins can initialize per-session state.
Closes#5592
16 callsites across 14 files were re-deriving the hermes home path
via os.environ.get('HERMES_HOME', ...) instead of using the canonical
get_hermes_home() from hermes_constants. This breaks profiles — each
profile has its own HERMES_HOME, and the inline fallback defaults to
~/.hermes regardless.
Fixed by importing and calling get_hermes_home() at each site. For
files already inside the hermes process (agent/, hermes_cli/, tools/,
gateway/, plugins/), this is always safe. Files that run outside the
process context (mcp_serve.py, mcp_oauth.py) already had correct
try/except ImportError fallbacks and were left alone.
Skipped: hermes_constants.py (IS the implementation), env_loader.py
(bootstrap), profiles.py (intentionally manipulates the env var),
standalone scripts (optional-skills/, skills/), and tests.
Follow-up to PR #5470. Replaces hardcoded ~/.hermes/.env references with
display_hermes_home() for correct behavior under profiles. Also updates
PluginManifest.requires_env type hint to List[Union[str, Dict[str, Any]]]
to document the rich format introduced in #5470.
- Rename per-LLM-call hooks from pre_llm_request/post_llm_request for clarity vs pre_llm_call
- Emit summary kwargs only (counts, usage dict from normalize_usage); keep env_var_enabled for HERMES_DUMP_REQUESTS
- Add is_truthy_value/env_var_enabled to utils; wire hermes_cli.plugins._env_enabled through it
- Update Langfuse local setup doc; add scripts/langfuse_smoketest.py and optional ~/.hermes plugin tests
Made-with: Cursor
Add ctx.register_cli_command() to PluginContext for general plugins and
discover_plugin_cli_commands() to memory plugin system. Plugins that
provide a register_cli(subparser) function in their cli.py are
automatically discovered during argparse setup and wired into the CLI.
- Remove 95-line hardcoded honcho argparse block from main.py
- Move honcho subcommand tree into plugins/memory/honcho/cli.py
via register_cli() convention
- hermes honcho setup now redirects to hermes memory setup (unified path)
- hermes honcho (no subcommand) shows status instead of running setup
- Future plugins can register CLI commands without touching core files
- PluginManager stores CLI registrations in _cli_commands dict
- Memory plugin discovery scans cli.py for register_cli at argparse time
main.py: -102 lines of hardcoded plugin routing
Plugin context from pre_llm_call hooks was injected into the system
prompt, breaking the prompt cache prefix every turn when content
changed (typical for memory plugins). Now all plugin context goes
into the current turn's user message — the system prompt stays
identical across turns, preserving cached tokens.
The system prompt is reserved for Hermes internals. Plugins
contribute context alongside the user's input.
Also adds comprehensive documentation for all 6 plugin hooks:
pre_tool_call, post_tool_call, pre_llm_call, post_llm_call,
on_session_start, on_session_end — each with full callback
signatures, parameter tables, firing conditions, and examples.
Supersedes #5138 which identified the same cache-busting bug
and proposed an uncached system suffix approach. This fix goes
further by removing system prompt injection entirely.
Co-identified-by: OutThisLife (PR #5138)
The plugin system defined six lifecycle hooks but only pre_tool_call and
post_tool_call were invoked. This activates the remaining four so that
external plugins (e.g. memory systems) can hook into the conversation
loop without touching core code.
Hook semantics:
- on_session_start: fires once when a new session is created
- pre_llm_call: fires once per turn before the tool-calling loop;
plugins can return {"context": "..."} to inject into the ephemeral
system prompt (not cached, not persisted)
- post_llm_call: fires once per turn after the loop completes, with
user_message and assistant_response for sync/storage
- on_session_end: fires at the end of every run_conversation call
invoke_hook() now returns a list of non-None callback return values,
enabling pre_llm_call context injection while remaining backward
compatible (existing hooks that return None are unaffected).
Salvaged from PR #2823.
Co-authored-by: Nicolò Boschi <boschi1997@gmail.com>
Reverts the sanitizer addition from PR #2466 (originally #2129).
We already have _empty_content_retries handling for reasoning-only
responses. The trailing strip risks silently eating valid messages
and is redundant with existing empty-content handling.
