| name | dev-standards-memory-needs-source |
| description | New memory entries need ISO 8601 timestamp + source-event tag (loop-id/task-id/commit-sha) for temporal conflict resolution. Soft guidance — backfill on next touch. Use when: writing new memory, creating per-memory file, reviewing PR adding memory, subagent appending memory. Skip: existing files lacking fields, CLAUDE.md preferences. |
Memories Require Timestamp and Source
Project-level soft-guidance rule for the memory layer. Memory entries that lack temporal grounding silently accumulate staleness — six months from now, the entry "this project uses OAuth" still claims OAuth even after the project moved to API keys, because no field tells the conflict-resolver "the OAuth claim is older than the new evidence." Adding a timestamp + source-event tag at write time is the cheapest possible insurance against that failure mode.
Provenance
- K2 design doc:
docs/research/K2-knowledge-hygiene-from-papers.md §3.4 (Temporal normalization — date-bearing claims must be tagged "as of date X" rather than ambient-present-tense)
- Source paper: OmniMEM
(2604.01007) — lifelong-multimodal-agent framing requires memory to survive across sessions, which requires temporal grounding to detect drift.
- Sibling plugin pattern:
plugins/research/agents/learnings-researcher.md verified_at + verified_against fields (commit d3c4669) and plugins/research/agents/session-historian.md surfaced_from.{session_id, session_date} shape (same commit). Those patterns are the upstream sibling discipline this rule formalizes for the memory layer.
- Reused contract: ideation and
present:mini-ide review flows define the source-event tag vocabulary — git:sha, memory:id, file:path:line, web:url, literal "guess". The source-event tag in this rule reuses that vocabulary, extended with loop:<id>, task:<dart-id>, and conversation:<id> for memory-specific sources.
The Soft-Guidance Rule
A new memory entry should carry both a written_at ISO 8601 timestamp and a source_event tag identifying what produced it. The pair is the minimum metadata required for downstream conflict resolution to be temporally aware. Existing memory entries without these fields are not retroactively rewritten; they are backfilled when the file is next touched for any other reason.
This is soft guidance (should, not must) because the memory layer is append-mostly and bulk rewrites would churn the git history without proportionate value. The rule applies to new writes; existing files migrate gradually.
Field Shapes
The two fields are kept simple — string + string — to avoid breaking existing parsers that read MEMORY.md as plain markdown. Both are encoded as a small frontmatter or inline-tag block at the head of each memory entry.
Field 1 — written_at
ISO 8601 UTC timestamp at the time the memory entry was created. Format:
written_at: 2026-04-26T15:30:00Z
- Granularity: date-only (
2026-04-26) is acceptable for low-frequency memory; full timestamp is preferred for high-frequency entries that may be written multiple times per day.
- Timezone: UTC (
Z suffix) is preferred to avoid timezone ambiguity across contributors. Local timezones are accepted with explicit offset (-07:00) when the memory captures wall-clock significance.
- Updates: when a memory entry is meaningfully revised (not a typo fix), append a
revised_at field rather than overwriting written_at. The original write time is the temporal anchor for staleness calculations.
Field 2 — source_event
A tag identifying what produced this memory. Reuses the standard provenance vocabulary, extended for memory-layer specifics:
| Form | Example | When to use |
|---|
loop:<id> | loop:pUtvC2dRaW1P | Memory written during a Ralph Wiggum loop — captures which loop produced the lesson |
task:<dart-id> | task:6mgXiXbw9G1B | Memory written during a single Dart-task execution outside a loop |
conversation:<id> | conversation:abc123def456 | Memory written during an ad-hoc conversation that has a session/conversation identifier |
git:<sha> | git:b28aa0f | Memory tied to a specific commit (e.g., "this pattern was introduced in b28aa0f") |
file:<path>:<line> | file:plugins/research/agents/web-researcher.md:42 | Memory citing a specific file location as its origin |
web:<url> | web:https://example.com/post | Memory derived from a web source |
guess | literal guess | Memory the author cannot trace to a specific event — uses the same literal-guess discipline as <PROVENANCE-CONTRACT> for unverifiable inferences |
Multi-source memories can carry an array: source_event: [loop:pUtvC2dRaW1P, git:b28aa0f]. Order does not matter; downstream consumers treat the array as a set.
Encoding Patterns
The two fields can appear in any of three forms depending on the memory file's existing structure:
Pattern A — YAML frontmatter (per-memory files)
For per-memory files under .claude/projects/<project>/memory/, use YAML frontmatter:
---
written_at: 2026-04-26T15:30:00Z
source_event: loop:pUtvC2dRaW1P
---
# Memory Title
Memory body.
Pattern B — Inline tag block (MEMORY.md entries)
For entries inside a shared MEMORY.md (where each entry is one bullet or section), prepend an inline tag line:
- [feature_name](feature_name.md) `[written_at: 2026-04-26 source_event: task:6mgXiXbw9G1B]` — One-line description.
This keeps MEMORY.md scannable while still carrying the metadata.
Pattern C — Section-header tag (longer entries)
For longer entries with their own section heading inside a shared file:
## Decision: switch from OAuth to API keys
**written_at:** 2026-04-26T15:30:00Z
**source_event:** git:b28aa0f, loop:pUtvC2dRaW1P
Body text...
Pick the form that least disrupts the existing file's structure. The point is the metadata, not the encoding.
What This Rule Does NOT Require
- Bulk rewrites of existing memory. Existing entries without these fields are valid-but-untyped. Backfill happens opportunistically when the file is touched for any other reason.
- Sub-second precision. Date-only timestamps are fine for most memory. Sub-second precision is over-engineering for a layer that decays on the scale of weeks-to-months.
- Cryptographic source attestation. The
source_event tag is for audit, not authentication. A loop-id or task-id is sufficient; signed attestations are out of scope.
- A new tool to enforce the rule. This is guidance for human reviewers and skill-using subagents. No hooks, no validators, no pre-commit gates are added by this rule. Enforcement is conventional, eat-your-own-dogfood-style.
Interaction With Existing Memory
The project's existing memory files are a mix of timestamped (feedback_*.md typically have an implicit timestamp via git history) and untimestamped (reference_*.md, project_*.md). The migration plan is:
- New entries (post this rule): carry both fields from the start.
- Existing entries (pre this rule): unchanged. When next touched for any other reason — e.g., revision, reformatting, citation by another rule — backfill
written_at from git log --follow --diff-filter=A -- <file> (file creation date) and source_event: git:<creation-sha> as the safest default.
- MEMORY.md index file: can be backfilled in one pass when convenient, but is not blocking. The index references files; the files carry the canonical metadata.
Worked Example
Before this rule:
## Feedback
- [No allowed-tools in skills](feedback_no_allowed_tools_skills.md) - Skills must not use allowed-tools; recommend tools, don't block them
After this rule (using Pattern B inline-tag form):
## Feedback
- [No allowed-tools in skills](feedback_no_allowed_tools_skills.md) `[written_at: 2026-02-14 source_event: task:Yk8Lq2NaH1Pk]` — Skills must not use allowed-tools; recommend tools, don't block them
The cost is one inline tag block per entry. The benefit is that six months from now, when a new memory entry contradicts this one, a conflict-detector can compare timestamps and pick the more recent claim — or, if both are recent, escalate to the user as a real conflict rather than silently picking one.
Anti-Patterns
| Anti-pattern | Why it fails |
|---|
| Bulk-rewriting all existing memory in one PR to add timestamps | Churns git history without proportionate value; opportunistic backfill is cheaper. |
Using written_at: now (literal string) instead of an actual ISO date | The conflict-detector cannot order memories by now; the field becomes useless. |
Using source_event: claude or source_event: anthropic (too coarse) | Tag must identify a specific event (a particular loop, task, commit, or conversation), not a class of events. |
Adding a confidence field as well | Out of scope here. Memory confidence is handled by the consumer (e.g., learnings-researcher's verified_at staleness rules); the memory layer itself carries only timestamp + source. Adding more fields is scope creep. |
| Treating the rule as a hard pre-commit gate | This is soft guidance. The rule says "should", not "must". Reviewers nudge new entries toward the shape; they do not block PRs over missing tags. |
Relationship To Other Skills
knowledge-hygiene:multi-source-research/SKILL.md — operates on retrieved sources at synthesis time; this rule operates on the memory layer at write time. Together they form the temporal-normalization → multi-source → conflict-detect pipeline.plugins/research/agents/learnings-researcher.md — verified_at + 90-day staleness threshold pattern. This rule is the analogous discipline for the memory layer (with no fixed staleness threshold — memory decay is consumer-specific, not layer-wide).plugins/research/agents/session-historian.md — surfaced_from.{session_id, session_date} pattern with 30-day staleness. Same family of disciplines; this rule is the project-memory-layer member.no-compression-on-skill-frontmatter (sibling skill) — applies to skill metadata; this rule applies to memory metadata. Both protect downstream retrievers from silent degradation.
