fix(agent): capture on_pre_compress return value and pass to compressor

[hbtjm9000]

What does this PR do?

Captures the return value of MemoryProvider.on_pre_compress() and passes it through to the context compressor's summarization prompt. Previously, the return value was silently discarded — every memory plugin returning compression context was broken without any error.

The fix threads memory_context through three layers:

1. run_agent.py — capture return value as pre_compress_context
2. ContextCompressor.compress() — accept memory_context parameter
3. ContextCompressor._generate_summary() — inject into compression prompt

Related Issue

Fixes #7192

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)

Changes Made

run_agent.py (+28 lines)

• Capture on_pre_compress() return value as pre_compress_context
• Pass memory_context=pre_compress_context to self._context_compressor.compress()

agent/context_compressor.py (+36 lines)

• compress(): add memory_context: str = "" parameter + docstring note
• _generate_summary(): add memory_context: str = "" parameter
• Template: inject ## Memory Provider Context section when non-empty (using pre-defined variable to avoid Python 3.11 f-string backslash restriction)
• All 3 retry call sites: pass memory_context through

tests/agent/test_context_compressor.py (+83 lines)

• TestOnPreCompressIntegration class with 3 tests:
  • test_compress_accepts_memory_context_kwarg
  • test_generate_summary_injects_memory_context_into_prompt
  • test_empty_memory_context_does_not_add_section

How to Test

cd hermes-agent
source venv/bin/activate
python -m pytest tests/agent/test_context_compressor.py::TestOnPreCompressIntegration -v

All 75 existing tests continue to pass.

Checklist

• fix(agent): Conventional Commits
• No duplicate PRs
• Only changes related to this fix
• pytest tests/agent/test_context_compressor.py -q passes
• Tests added
• No config keys, docs, or schemas changed (bug fix restoring documented behavior)

[alt-glitch]

Competing with #7195 and #11236 for the same fix (issue #7192). All address on_pre_compress() return value being silently discarded.

[teknium1]

Thanks for identifying a real contract break: MemoryProvider.on_pre_compress() and MemoryManager.on_pre_compress() explicitly return text intended for the compression prompt (agent/memory_provider.py:220-230, agent/memory_manager.py:883-900). Current main still discards it at agent/conversation_compression.py:631-644.

Problems

• The PR applies the handoff in run_agent.py, but compression orchestration was extracted to agent/conversation_compression.py by 5311d9959e19477aac8aa7deca46c1ee0b8e7000. The current production path will need the handoff there.
• The added compressor-only tests do not exercise that orchestrator boundary, where the defect currently exists.

Suggested changes

• Port the capture and forwarding logic to agent/conversation_compression.py:631-644, then thread it through ContextCompressor.compress() and _generate_summary() including retry paths.
• Add an orchestration regression test with a provider returning a sentinel and assert the summarizer prompt receives it.

This is an automated hermes-sweeper review.

[teknium1]

Please add a regression test for the actual orchestration boundary: a MemoryManager/provider returning a sentinel must cause the current compression flow to place that sentinel in the summary prompt. The production defect is now at agent/conversation_compression.py:631-644, so direct ContextCompressor.compress() coverage alone would not catch a dropped handoff.

[teknium1]

This fix has landed on main via PR #67938 (salvaged from PR #64342 by @GottZ, which consolidated the on_pre_compress return-value forwarding with sanitization, engine-signature compatibility, and lock hardening).

Your PR correctly identified the same root cause — the provider's return value being silently discarded before compression. The merged implementation supersedes this one, so closing it. First-submitter credit goes to @jairodriguez (#11236, Apr 16); thank you for the independent confirmation and fix.