Follow-up to the salvaged #57634 commits:
- agent/manual_compression_feedback.py: new describe_compression_lock_skip()
— single source of truth for lock-skip wording. A descriptive holder
string means another compressor CONFIRMED holds the lock ('already in
progress (holder: ...)'); True/None means acquisition failed without a
confirmed holder (hermes_state.try_acquire_compression_lock catches
sqlite3.Error internally and returns False), so the message says
'could not acquire ... the lock check failed' instead of falsely
claiming a concurrent compression is running.
- cli.py, gateway/slash_commands.py, tui_gateway/server.py (all three
in-process consumers: session.compress RPC, command.dispatch compress
branch, slash.exec mirror) now route through the shared helper.
- tui_gateway/server.py command.dispatch compress branch: catch
CompressionLockHeld explicitly — it previously fell into the generic
'compress failed' error handler.
- Deferred-notify contract (#69324): lock-skip discards the pending
context-engine notification (committed=False) in _compress_session_history
and the CLI path before returning.
- tests: lock-skip wording pins per surface, VISIBLE_COMPRESSION_MESSAGES
noise-filter carve-outs for both wordings, MagicMock signal opt-outs for
sibling tests added on main after the original PR.
The user-visible /compress banner and the post-compression last_prompt_tokens
writeback both counted only the raw message transcript (chars/4). With a 15KB
system prompt and 30 tool schemas (~26KB), a 4-message transcript that looks
like ~45 tokens to the transcript-only estimator is really ~10.5K tokens of
request pressure — a 234x gap.
Two user-facing consequences:
- Banner shows 'Compressing … (~45 tokens)…' while compression is actually
firing on 10K+ tokens of real pressure, confusing users about why
compression triggered (reported by @codecovenant on X; #6217).
- Post-compression last_prompt_tokens writeback omits tool schemas, so the
next should_compress() check compares real usage against a stale
underestimate — compression triggers late, potentially past the model's
context limit on small-context models (#14695).
Swap estimate_messages_tokens_rough() for estimate_request_tokens_rough()
at every user-visible banner and at the post-compression writeback.
estimate_request_tokens_rough() already existed for exactly this purpose
and includes system prompt + tool schemas.
Touched call sites:
- run_agent.py: post-compression last_prompt_tokens writeback, post-tool
call should_compress() fallback when provider usage is missing
- cli.py: /compress banner + summary
- gateway/run.py: gateway /compress banner + summary
- tui_gateway/server.py: TUI /compress status + summary
- acp_adapter/server.py: ACP /compact before/after
Left intentionally alone:
- Session-hygiene fallback and the 'no agent' /status path in gateway/run.py
— no agent instance is in scope to query for system prompt/tools, and the
existing 30-50% overestimate wobble on hygiene is safety-accepted.
- Verbose-mode 'Request size' logging — informational only, already counts
system prompt via api_messages[0].
Also relabels the feedback line from 'Rough transcript estimate' to
'Approx request size' so the metric label matches what it actually measures.
Credits: diagnoses from @devilardis (#14695) and @Jackten (#6217);
user report @codecovenant on X (2026-04-30).
Closes#14695Closes#6217
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