fix(memory): honor read_only on update and recall access times (#7368)

[roli-lpci]

Fixes #7368.

Summary

Memory.read_only currently blocks remember and remember_many, but update still rewrites records and recall still persists last_accessed via touch_records. This change makes those two implicit mutation paths honor read_only while leaving explicit deletion through forget and reset unchanged.

Why

A caller using Memory as a read-only retrieval surface should not leave a persistent trace merely by reading. The existing read barrier and reset guards show that the omitted checks were inconsistent with the flag rather than an intentional latency exemption.

Tests

• Added regression coverage proving update is a no-op in read-only mode.
• Added positive coverage that writable update still works.
• Added regression coverage proving read-only recall does not refresh last_accessed, with a writable positive control.
• pytest lib/crewai/tests/memory: 134 passed, 19 skipped.
• ruff: clean.
• hermes-gate fast and review: PASS, zero findings.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: 677ddfd6-88f2-4d8e-9d10-444b70a74690

📥 Commits

Reviewing files that changed from the base of the PR and between a8d330d and 5a6860a.

📒 Files selected for processing (2)

• lib/crewai/src/crewai/memory/unified_memory.py
• lib/crewai/tests/memory/test_unified_memory.py

Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.

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📝 Walkthrough

Walkthrough

Memory.read_only now blocks implicit writes from update() and recall(). Documentation describes the behavior, and regression tests cover read-only no-ops plus writable positive controls.

Changes

Read-only memory behavior

Layer / File(s)	Summary
Read-only operation guards lib/crewai/src/crewai/memory/unified_memory.py	update() returns the existing record without changes when read-only. recall() skips access-time refresh. The field documentation describes these rules.
Read-only behavior validation lib/crewai/tests/memory/test_unified_memory.py	Tests verify read-only update and recall behavior, plus writable update and recall behavior.

Suggested reviewers: joaomdmoura

Severity of issue fixed: Medium

Merge Risk: ⚪ Minimal · up to 4e7c1

Read-only memory now leaves records and access timestamps unchanged for update and recall operations, while writable behavior remains covered. No merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the two main changes: honoring read_only in update() and preventing recall() access-time writes.
Description check	✅ Passed	The description includes the linked issue, change summary, rationale, verification results, and test coverage. It does not include a separate Additional context section, but the required information i…
Linked Issues check	✅ Passed	The changes satisfy issue #7368. Read-only update() returns the existing record without mutation, read-only recall() skips access-time persistence, explicit deletion remains unchanged, and regression …
Out of Scope Changes check	✅ Passed	The changes are limited to the read_only behavior in Memory, related documentation, and focused regression tests. No unrelated code changes are identified.
Docstring Coverage	✅ Passed	Docstring coverage is 85.71% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 2 files.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[Vidit-Ostwal]

@lorenzejay Mind taking a look?

[Vidit-Ostwal]

Approved. This correctly makes Memory.read_only prevent update writes and recall access-time writes, with focused regression coverage.