The v2 'single POST /v2/{users|groups}/{id}/files' upload path is capped
at ~10 MB inline (base64 'file_data' or 'url'). For larger files the QQ
platform provides a three-step flow:
1. POST /upload_prepare → upload_id + pre-signed COS part URLs
2. PUT each part to its COS URL → POST /upload_part_finish
3. POST /files with {upload_id} → file_info token
This commit adds a new gateway/platforms/qqbot/chunked_upload.py module
that implements the flow, wires it into QQAdapter._send_media for local
files (URL uploads keep the existing inline path), and introduces
structured exceptions so the caller can surface actionable error text:
- UploadDailyLimitExceededError (biz_code 40093002, non-retryable)
- UploadFileTooLargeError (file exceeds the platform limit)
Both carry file_name / file_size_human / limit_human so the model can
compose user-friendly replies instead of seeing opaque HTTP codes.
The part_finish 40093001 retryable-error loop respects the server-
provided retry_timeout (capped at 10 minutes locally) with a 1 s
polling interval. COS PUTs retry transient failures up to 2 times
with exponential backoff. complete_upload retries up to 2 times.
Covers files up to the platform's ~100 MB per-file limit; before this
the adapter silently rejected anything over ~10 MB.
19 new unit tests under TestChunkedUpload* cover the happy path,
prepare-response parsing, helper functions, part retries, COS PUT
retries, group vs c2c routing, and the structured-error mapping.
Co-authored-by: WideLee <limkuan24@gmail.com>
Adds a per-task override for the consecutive-failure circuit breaker,
so individual tasks can opt out of the global ``kanban.failure_limit``
without dragging everyone else with them.
Resolution order (now three tiers):
1. per-task ``max_retries`` (new, this commit)
2. caller-supplied ``failure_limit`` — the gateway threads
``kanban.failure_limit`` from config here
3. ``DEFAULT_FAILURE_LIMIT`` (2)
Changes:
- ``tasks.max_retries INTEGER`` column + migration for existing DBs
(NULL = no override, matches pre-column behavior).
- ``Task.max_retries`` field + ``from_row`` plumbing.
- ``create_task(..., max_retries=N)`` kwarg.
- ``_record_task_failure`` reads the per-task value first and records
``limit_source`` + ``effective_limit`` on the ``gave_up`` event so
operators can see which tier won.
- CLI: ``hermes kanban create --max-retries N`` (rejects ``< 1``).
- CLI: ``hermes kanban show`` surfaces the effective threshold +
source (``(task)``, ``(config kanban.failure_limit)``, ``(default)``).
- CLI: ``_task_to_dict`` includes ``max_retries`` in ``--json`` output.
Key design choice vs. the earlier #20972 attempt:
- No new config key. The existing ``kanban.failure_limit`` (landed in
#21183) is the dispatcher-tier source — no silent break for users
who already tuned it.
- No ``!=`` sentinel for "is config set" (which would misfire when
config equals the default). The tier-winner is determined purely
by "is per-task override set" — the dispatcher always wins when
per-task is NULL, regardless of whether the caller passed the
default or a configured value.
E2E verified across four scenarios: default-only (trips at 2),
config-only (trips at caller's value), per-task-only beats default
(trips at task value), per-task beats larger config (trips at task
value). ``gave_up`` event metadata correctly records ``limit_source``
and ``effective_limit`` in all cases.
Tests:
- ``test_per_task_max_retries_overrides_dispatcher_limit`` — task=1
beats caller=10.
- ``test_per_task_max_retries_allows_more_than_default`` — task=5
does not trip at caller=default of 2.
- ``test_max_retries_none_falls_through_to_dispatcher_limit`` — None
honors caller's config value (4), records ``limit_source=dispatcher``.
Full kanban trio (db + core + cli + tools + dashboard-plugin): 342
passed, no regressions.
Supersedes: #20972 (@jelrod27) — credit in PR close comment.
Ref: #20263 (tangentially — the reporter asked about adapter API
drift, not retry caps, but the CLI discussion there is what
surfaced the original ask).
PairingStore.approve_code() didn't consult _is_locked_out(), so after
MAX_FAILED_ATTEMPTS bad approvals the lockout flag was set but a valid
code still got accepted — any pending code (legitimately issued or
attacker-obtained) could be approved during the 1-hour lockout window,
nullifying the brute-force protection.
- gateway/pairing.py: lockout check runs in approve_code() right after
_cleanup_expired, before the pending lookup. Returns None on lockout.
- tests/gateway/test_pairing.py: test_lockout_blocks_code_approval pins
the regression — reporter's exact reproducer (generate valid code,
exhaust attempts with WRONGCODE, try to approve valid code) must
return None and leave is_approved == False. Also pins recovery: once
lockout expires, the still-pending code approves normally.
- hermes_cli/pairing.py: _cmd_approve distinguishes the two None cases.
On lockout, prints 'Platform locked out... clears in N minutes. To
reset sooner, delete the _lockout:<platform> entry from
_rate_limits.json' instead of the misleading 'Code not found or
expired' message. 29/29 pairing tests pass; E2E-verified with
reporter's exact Python reproducer.
Adds Google Chat as a new gateway platform, shipped under
plugins/platforms/google_chat/ following the canonical bundled-plugin
pattern (Teams, IRC). Rewired from the original PR #18425 to use the
new env_enablement_fn + cron_deliver_env_var plugin interfaces landed
in the preceding commit, so the adapter touches ZERO core files.
What it does:
- Inbound DM + group messages via Cloud Pub/Sub pull subscription (no
public URL needed), with attachments (PDFs, images, audio, video)
downloaded through an SSRF-guarded Google-host allowlist.
- Outbound text replies with the 'Hermes is thinking…' patch-in-place
pattern — no tombstones.
- Native file attachment delivery via per-user OAuth. Google Chat's
media.upload endpoint rejects service-account auth, so each user
runs /setup-files once in their own DM to grant
chat.messages.create for themselves; the adapter then uploads as
them. Tokens stored per email at
~/.hermes/google_chat_user_tokens/<email>.json.
- Thread isolation: side-threads get isolated sessions, top-level DM
messages share one continuous session. Persistent thread-count
store survives gateway restart.
- Supervisor reconnect with exponential backoff.
- Multi-user out of the box.
How it plugs in (no core edits):
- env_enablement_fn seeds PlatformConfig.extra with project_id,
subscription_name, service_account_json, and the home_channel dict
(which the core hook turns into a HomeChannel dataclass). Reads
GOOGLE_CHAT_PROJECT_ID (falls back to GOOGLE_CLOUD_PROJECT),
GOOGLE_CHAT_SUBSCRIPTION_NAME (falls back to GOOGLE_CHAT_SUBSCRIPTION),
GOOGLE_CHAT_SERVICE_ACCOUNT_JSON (falls back to
GOOGLE_APPLICATION_CREDENTIALS), GOOGLE_CHAT_HOME_CHANNEL.
- cron_deliver_env_var='GOOGLE_CHAT_HOME_CHANNEL' gets cron delivery
for free — cron/scheduler.py consults the platform registry for any
name not in its hardcoded built-in sets.
- plugin.yaml's rich requires_env / optional_env blocks auto-populate
OPTIONAL_ENV_VARS via the new hermes_cli/config.py injector, so
'hermes config' UI surfaces them with description / url / prompt /
password metadata.
- Module-level Platform('google_chat') call in adapter.py triggers the
Platform._missing_() registration so Platform.GOOGLE_CHAT attribute
access works without an enum entry.
Distribution: ships inside the existing hermes-agent package. Users
opt in via 'pip install hermes-agent[google_chat]' and follow the
8-step GCP walkthrough at
website/docs/user-guide/messaging/google_chat.md.
Test coverage: 153 tests in tests/gateway/test_google_chat.py, all
passing. Spans platform registration, env config loading, Pub/Sub
envelope routing, outbound send + chunking + typing patch-in-place,
attachment send paths, SSRF guard, thread/session model,
supervisor reconnect, authorization, per-user OAuth, and the new
plugin-registry cron delivery wiring.
Credit: adapter + OAuth + tests + docs authored by @donramon77
(PR #18425). Rewire onto the new plugin hooks + salvage commit by
Teknium.
Co-Authored-By: Ramón Fernández <112875006+donramon77@users.noreply.github.com>
MCP tool results can include ImageContent blocks (screenshots from
Playwright/Blockbench/Puppeteer etc). The tool result handler only
extracted block.text, so image blocks were silently dropped and the
agent saw an empty or text-only response — losing the actual payload.
Add _cache_mcp_image_block() that base64-decodes the block, validates
the bytes via gateway.platforms.base.cache_image_from_bytes (which
sniffs for PNG/JPEG/WebP signatures and rejects non-images), writes to
the shared `~/.hermes/cache/images/` dir, and returns a MEDIA:<path>
tag. The handler appends that tag to the result parts so downstream
gateway adapters render the image inline.
Logs and drops on malformed base64 / non-image payload rather than
raising — a single bad block shouldn't kill the tool call.
Distilled from #17915 (c3115644151) and #10848 (gnanirahulnutakki), both
too stale to cherry-pick (branches diverged enough to revert dozens of
unrelated fixes). Went with #10848's approach of plumbing through
Hermes' existing MEDIA tag / cache_image_from_bytes infrastructure
rather than #17915's raw tempfile path, because it integrates with the
remote-backend mount system and messaging adapters that already handle
MEDIA tags natively.
Co-authored-by: c3115644151 <c3115644151@users.noreply.github.com>
Co-authored-by: gnanirahulnutakki <gnanirahulnutakki@users.noreply.github.com>
* fix(mcp): re-raise CancelledError explicitly in MCPServerTask.run
On Python 3.11+, `asyncio.CancelledError` inherits from `BaseException`
(not `Exception`), so the broad `except Exception as exc:` in
`MCPServerTask.run`'s transport loop did NOT catch it. Task cancellation
from gateway restart / explicit `task.cancel()` silently escaped past
the reconnect logic — the MCP server task died without going through
the shutdown/reconnect code paths that check `_shutdown_event`.
Add an explicit `except asyncio.CancelledError: raise` before the broad
catch so cancellation propagation is self-documenting rather than an
accident of exception hierarchy, and future sibling-site work (e.g.
distinguishing shutdown-cancel from transport-cancel) has an obvious
hook. Behavior on pre-3.8 Pythons where CancelledError WAS an Exception
subclass is also corrected: the old path would have caught it and
treated it as a connection failure worth retrying.
Closes#9930.
* fix(mcp): forward OAuth auth and bump sse_read_timeout on SSE transport
Two surgical correctness bugs in the SSE branch of MCPServerTask._run_http,
distilled from @amiller's PR #5981 that couldn't be cherry-picked wholesale
(branch too stale).
1. sse_read_timeout was set to the tool timeout (default 60s). That's the
wrong dimension — it governs how long sse_client will wait between
events on the SSE stream, not per-call latency. SSE servers routinely
hold the stream idle for minutes between events; a 60s read timeout
drops the connection after the first slow stretch (Router Teamwork,
Supermemory on Cloudflare Workers idle-disconnect at ~60s). Bump to
300s to match the Streamable HTTP path's httpx read timeout.
2. OAuth auth was built via get_manager().get_or_build_provider() but
never forwarded to sse_client. SSE MCP servers behind OAuth 2.1 PKCE
would silently fail with 401s on every request.
Keepalive (the other half of #5981) intentionally left for a follow-up —
it's a real improvement but a bigger change, and these two are obvious
corrections to ship now. Credits to @amiller.
Co-authored-by: Andrew Miller <socrates1024@gmail.com>
---------
Co-authored-by: Andrew Miller <socrates1024@gmail.com>
On Python 3.11+, `asyncio.CancelledError` inherits from `BaseException`
(not `Exception`), so the broad `except Exception as exc:` in
`MCPServerTask.run`'s transport loop did NOT catch it. Task cancellation
from gateway restart / explicit `task.cancel()` silently escaped past
the reconnect logic — the MCP server task died without going through
the shutdown/reconnect code paths that check `_shutdown_event`.
Add an explicit `except asyncio.CancelledError: raise` before the broad
catch so cancellation propagation is self-documenting rather than an
accident of exception hierarchy, and future sibling-site work (e.g.
distinguishing shutdown-cancel from transport-cancel) has an obvious
hook. Behavior on pre-3.8 Pythons where CancelledError WAS an Exception
subclass is also corrected: the old path would have caught it and
treated it as a connection failure worth retrying.
Closes#9930.
PR #21238 introduced top-level `allOf: [{if/then/required}]` blocks in the
built-in memory tool's parameters schema as conditional-required hints.
Two problems:
1. OpenAI's Codex backend (chatgpt.com/backend-api/codex, gpt-5.x) rejects
top-level `allOf`/`anyOf`/`oneOf`/`enum`/`not` outright with a
non-retryable 400 — affected every user on openai-codex/gpt-5.x.
2. The `if/then` hints were silently ignored by every other provider
(Chat Completions doesn't honour them on function schemas), so they
never actually enforced anything anywhere.
The runtime handler in `memory_tool()` already validates the per-action
required fields and returns actionable error messages, so removing the
block changes nothing behaviourally.
Paired with the defense-in-depth sanitizer in the previous commit, this
closes the bug both at the source (schema no longer emits the forbidden
form) and at the wire boundary (sanitizer strips it if anything else
re-introduces it).
- Rewrites `tests/tools/test_memory_tool_schema.py` to guard against
regressing the forbidden-combinator shape instead of asserting it.
- Adds AUTHOR_MAP entry for @hrkzogw (author of the sanitizer fix).
Mirrors the Slack `allowed_channels` feature (PR #7401) and Discord's
`allowed_channels` (PR #7044) across the remaining group-capable platforms.
All five platforms (Slack + Discord + the four added here) now follow the
same pattern: primary config via config.yaml, env-var fallback as an escape
hatch — matching the project policy that .env is for secrets only and
behavioral settings belong in config.yaml.
Also fixes a duplicate `slack` key in DEFAULT_CONFIG introduced by PR
#7401 (the later entry silently overwrote `allowed_channels`, `require_mention`,
and `free_response_channels` at dict-literal evaluation time).
Platforms added:
- Telegram: `telegram.allowed_chats` (env alias: `TELEGRAM_ALLOWED_CHATS`)
- Mattermost: `mattermost.allowed_channels` (env alias: `MATTERMOST_ALLOWED_CHANNELS`)
- Matrix: `matrix.allowed_rooms` (env alias: `MATRIX_ALLOWED_ROOMS`)
- DingTalk: `dingtalk.allowed_chats` (env alias: `DINGTALK_ALLOWED_CHATS`)
Mattermost and Matrix previously had NO config.yaml bridging for any of
their gating settings; this PR adds `load_gateway_config` bridges for them
(Mattermost gets require_mention + free_response_channels + allowed_channels;
Matrix gets allowed_rooms on top of its existing bridges for require_mention
and free_response_rooms).
Semantics identical everywhere:
- Empty = no restriction (fully backward compatible).
- Non-empty = hard whitelist: non-listed chats are silently ignored,
even when the bot is @mentioned.
- DMs bypass the check entirely.
DEFAULT_CONFIG merges the duplicate `slack` block and adds new `mattermost`
and `matrix` blocks so all gating settings surface in defaults.
Not included: Feishu (has its own per-chat `chat_rules` system that covers
this use case differently), WhatsApp (already has `group_allow_from` via
`group_policy: allowlist`), pure-DM platforms (Signal, SMS, BlueBubbles,
Yuanbao — no group concept).
When the parent agent uses a composite toolset like hermes-cli, calling
delegate_task with individual toolsets (e.g. web, terminal) resulted in
zero tools because the name-based intersection failed: 'web' != 'hermes-cli'.
Add _expand_parent_toolsets() which collects all tool names from parent
toolsets, then recognises any individual toolset whose tools are a subset
of the parent's available tools. This allows delegate_task(toolsets=['web'])
to work correctly when the parent has hermes-cli enabled.
Fixes#19447
Add tencent/hy3-preview (without :free suffix) as a paid model route
alongside the existing free variant. This allows seamless transition
when the model moves from free to paid on OpenRouter — both routes
coexist so neither side's timing causes breakage.
Changes:
- models.py: add ("tencent/hy3-preview", "") to OPENROUTER_MODELS
- model-catalog.json: add paid variant entry
- tests: add assertions for paid route presence
The :free entry can be removed in a follow-up PR once OpenRouter
confirms the free route is deprecated.
Co-authored-by: simonweng <simonweng@tencent.com>
Some exception classes (e.g. anyio.ClosedResourceError) are raised without
a message argument, so str(exc) returns an empty string. The existing error
format f'{type(exc).__name__}: {exc}' would produce messages like
'MCP call failed: ClosedResourceError: ' with nothing after the colon.
Add _exc_str() helper that falls back to repr(exc) when str(exc) is empty,
and apply it to all 6 MCP error formatting sites (5 tool/prompt/resource
handlers + 1 sampling handler).
Fixes#19417
Treat closed-resource, closed-transport, broken-pipe, and EOF MCP failures as stale session equivalents so the existing reconnect/retry-once path can recover. Add regression coverage for the stale-pipe marker variants.\n\nChecks:\n- python -m py_compile tools/mcp_tool.py tests/tools/test_mcp_tool_session_expired.py\n- python -m pytest tests/tools/test_mcp_tool_session_expired.py -q -o addopts=\n- selected secret scan over touched files
Track elapsed wall time in _run_on_mcp_loop, cancel the in-flight future when a timeout expires, and raise a descriptive TimeoutError that includes the elapsed and configured timeout. Add regression coverage for the new timeout diagnostics.
## Summary
- Forwards chat-completions `timeout` into the Codex Responses stream call.
- Adds total elapsed-time enforcement while the Responses stream is still yielding events.
- Closes the underlying client on timeout to unblock stalled streams, then raises `TimeoutError`.
- Adds focused tests for timeout forwarding and total timeout enforcement.
## Why
The Codex auxiliary adapter can be used by non-interactive auxiliary work such as context compression. If the stream keeps yielding progress-like events but never completes, SDK socket/read timeouts do not necessarily protect the full operation. This makes the CLI look stuck until the user force-interrupts the whole session.
This is a refreshed upstream-ready version of the earlier fork fix around `d3f08e9a0` / PR #3.
## Verification
- `python -m py_compile agent/auxiliary_client.py tests/agent/test_auxiliary_client.py`
- `python -m pytest -o addopts='' tests/agent/test_auxiliary_client.py::TestCodexAuxiliaryAdapterTimeout -q`
- `git diff --check`
Discord (and similar platforms) can serve a PNG image cached as
discord_xxx.webp because the CDN reports content_type=image/webp for
proxied stickers, custom emoji, and certain bot-uploaded images even
when the actual bytes are PNG. Hermes' agent.image_routing._guess_mime
trusted the file suffix and declared media_type=image/webp to
Anthropic, which strict-validates and returns:
HTTP 400 messages.N.content.M.image.source.base64:
The image was specified using the image/webp media type,
but the image appears to be a image/png image
The Discord image attachment never reaches the model; the whole turn
fails with no salvage path.
Fix: sniff magic bytes in _file_to_data_url before declaring MIME.
Suffix-based detection is kept as a fallback when bytes aren't
available. New helper _sniff_mime_from_bytes covers PNG, JPEG, GIF,
WEBP, BMP, and HEIC/HEIF.
Tests:
- Two existing tests asserted the old broken behaviour (PNG bytes in
a .jpg/.webp file should report jpeg/webp); rewritten with real
jpeg/webp magic bytes so they still cover suffix-aligned cases.
- New regression test test_mime_sniff_overrides_misleading_extension
reproduces the exact Discord scenario (PNG bytes, .webp suffix) and
asserts the data URL comes back as image/png.
All 28 tests in tests/agent/test_image_routing.py pass.
When the provider rejects a request (e.g. invalid model slug like
'--provider nous --model kimi-k2.6' where the valid slug is
'moonshotai/kimi-k2.6'), run_conversation() returns
{failed: True, error: <detail>, final_response: None}. The TUI gateway
and one-shot CLI mode both dropped the error on the floor and emitted
an empty turn, so the user saw a blank response with no indication
that anything went wrong.
Mirror the interactive CLI's existing pattern (cli.py:9832): when
final_response is empty AND (failed|partial) is set AND error is
populated, surface 'Error: <detail>' as the visible text. Leaves
the None-with-no-error path and the '(empty)' sentinel path
untouched — an empty successful turn still renders empty, and
existing sentinel handlers keep owning their lane.
Reported by @counterposition in PR #20873; taking a minimal fix
rather than the broader structured-failure refactor proposed there.
Per repo policy, ~/.hermes/.env is for secrets only. Guild IDs are
behavioral configuration, not secrets. Replacing the
DISCORD_DM_ROLE_AUTH_GUILD env var from the original fix with
discord.dm_role_auth_guild in config.yaml.
- New module-level _read_dm_role_auth_guild() helper reads
hermes_cli.config.read_raw_config()['discord']['dm_role_auth_guild'].
Fails closed on any parse error (safe default = DM role-auth off).
- DEFAULT_CONFIG['discord'] gains dm_role_auth_guild: '' with a comment
documenting the opt-in.
- Tests patch hermes_cli.config.read_raw_config directly (via the
_set_dm_role_auth_guild helper) instead of setenv/delenv. 12 tests
in test_discord_roles_dm_scope pass; no env var involvement.
- Docstring + module docstring + comments updated to reference
discord.dm_role_auth_guild.
- E2E verified with real imports across 6 scenarios: unset, int,
string, garbage, zero, and (crucially) env-var-only-no-config all
return None except the valid int/string cases. Env var has zero
effect — policy compliance confirmed.
Sibling-site fix: _evaluate_slash_authorization was the fourth
_is_allowed_user caller and didn't pass guild/is_dm through, so slash
interactions would take the DM branch regardless of whether they came
from a guild channel. Now reads interaction.guild + in_dm and forwards.
Also updates test_discord_slash_auth fixture (_make_interaction) so
the SimpleNamespace guild mock has a get_member(uid)->None method —
required by the new guild-scoped fallback path in _is_allowed_user.
Tests exercising positive role paths still work via user.roles.
Three new regression tests in test_discord_roles_dm_scope:
- Slash DM + role in mutual public guild → rejected
- Slash in guild B + role only in guild A → rejected
- Slash in guild B + role in guild B → allowed (positive control)
368 Discord tests pass. test_discord_free_channel_skips_auto_thread
also fails on clean main (pre-existing, unrelated to this fix).
The initial DISCORD_ALLOWED_ROLES implementation (#11608, merged from #9873)
scans every mutual guild when resolving a user's roles. This allows a
cross-guild DM bypass:
1. Bot is in both public server A and private server B.
2. User holds the allowed role in server A only.
3. User DMs the bot. The role check finds the role in A and authorizes the
DM, granting access as if the user were trusted in server B.
Fix:
- DMs (no guild context) disable role-based auth by default. Opt-in via
DISCORD_DM_ROLE_AUTH_GUILD=<guild_id> restricts role lookup to one
explicitly-trusted guild.
- Guild messages check roles only in the originating guild
(message.guild), never in other mutual guilds.
- Reject cached author.roles when the Member came from a different guild
than the current message.
Backwards compatibility:
- DISCORD_ALLOWED_USERS behavior is unchanged (still works in both DMs
and guild messages).
- Deployments that rely on roles in guild channels continue to work;
role checks are now strictly scoped to that guild.
- Deployments that intentionally want role-based DM auth can opt into a
single trusted guild via DISCORD_DM_ROLE_AUTH_GUILD.
Tests: 9 new regression guards in
tests/gateway/test_discord_roles_dm_scope.py covering the bypass path,
the opt-in path, cross-guild guild-message bypass, and backwards-compat
user-ID paths. 47/47 discord-auth tests pass.
Refs: #11608 (initial implementation), #7871 (feature request),
#9873 (PR author credit @0xyg3n)
Authenticated remote OpenViking servers derive tenancy from the Bearer
key, but the client was always sending X-OpenViking-Account and
X-OpenViking-User — defaulted to the literal string "default" — which
overrode the key-derived tenant and broke auth.
- _headers(): skip X-OpenViking-Account/-User when blank or "default"
(treats the legacy default value as unset, so existing installs don't
need to touch their .env)
- _headers(): send Authorization: Bearer <key> alongside X-API-Key for
standard HTTP auth compatibility
- health(): include auth headers so /health works against servers that
require authentication
Tests cover bearer emission, legacy "default" suppression, empty
suppression, real tenant passthrough, and authenticated health checks.
Fixes the same user report as #20695 (from @ZaynJarvis); that PR could
not be merged because its branch was stale against main and would have
reverted recent OpenViking work (#15696, local resource uploads, summary
URI normalization, fs-stat pre-check).
Cloud metadata endpoints (169.254.169.254 etc.) are now always blocked
by browser_navigate regardless of hybrid routing, allow_private_urls,
or backend.
Bug: commit 42c076d3 (#16136) added hybrid routing that flips
auto_local_this_nav=True for private URLs and short-circuits
_is_safe_url(). IMDS endpoints are technically private (169.254/16
link-local), so the sidecar happily routed them to a local Chromium,
and the agent could read IAM credentials via browser_snapshot. On
EC2/GCP/Azure this is a full SSRF-to-credential-theft.
Fix: new is_always_blocked_url() in url_safety.py — a narrow floor
that checks _BLOCKED_HOSTNAMES, _ALWAYS_BLOCKED_IPS,
_ALWAYS_BLOCKED_NETWORKS only. Applied as an independent gate in
browser_navigate's pre-nav and post-redirect checks, BEFORE
auto_local_this_nav gets a chance to short-circuit. Ordinary private
URLs (localhost, 192.168.x, 10.x, .local, CGNAT) still route to the
local sidecar as the #16136 feature intends.
Secondary fix (reporter's finding): _url_is_private() now explicitly
checks 172.16.0.0/12. ipaddress.is_private only covers that range on
Python ≥3.11 (bpo-40791), so on 3.10 runtimes those URLs were routed
to cloud instead of the local sidecar. No security impact — just a
correctness fix for the hybrid-routing feature.
Closes#16234.
