harvest-session-learnings

name	harvest-session-learnings
description	Scan the current working session and the active task's artifacts for reusable, generalizable lessons (what was tried, what failed and why, what surprised us, what the next task should do differently) and propose anchored entries to append to the task's LEARNINGS.md, the produce-side counterpart to the ADR-0017 consume path that task-init already reads. Append-only and read-only on existing entries; de-duplicates against what is already captured; keeps durable lessons and drops one-off task trivia. Use on demand mid-task after a hard-won fix or a surprising failure, or at closure to sweep a long session before the context is lost. Do not use to rewrite or prune existing learnings (never edit prior entries), to capture a single in-flight observation (use capture-observation), to close a slice or the task (use slice-closure or task-close), or when nothing durable was learned (return a NO_OP rather than manufacturing a lesson).
metadata	{"category":"execution-and-closure","primary-cursor-mode":"Ask","multi-repo-aware":false,"context-layers-consumed":["memory"],"context-layers-produced":["memory"],"tools":["Read","Write","Edit","Bash","Glob","Grep"],"x-wos-profiles":["core","full"],"provenance":"first-party","suggested-model":"claude-sonnet-4-6"}

Act as a senior/staff engineer running a focused retrospective sweep over the current session, distilling only the lessons worth carrying into future tasks.

Goal: Read the working session and the active task's artifacts, extract the reusable lessons (tried X, it failed because Y, next time Z), and propose anchored entries to append to the task's LEARNINGS.md. This is the produce-side counterpart to ADR-0017: task-init already reads prior LEARNINGS to seed a new task; this command is one explicit way those entries get written, complementing the inline ### Learnings that slice-closure captures per slice.

Mandatory context bootstrap (before any output):

• Read these sections in WORKFLOW_OPERATING_SYSTEM.md first:
  • ## LLM execution contract
  • ## Editor mode policy (mode definitions only; the tool mapping table is lazy-loaded in wos/editor-mode-mappings.md and needed only for non-Claude-Code tools)
  • ## Global output contract (including Adaptive handoff and Mode selection rule)
  • ## Cross-cutting workflow guardrails
• Bootstrap tiers (ADR-0025): the light-weight commands (branch-commit, what-next, where-we-at, slice-closure, compact-task-memory) may skip ## Editor mode policy good-fits lists and ## Cross-cutting workflow guardrails sequencing heuristics, reading only the mode definitions and the core guardrail rules (routing memory, command-less input triage, official command names, material change, no-op). The full tier is measured at 9610 tokens: the combined size of the four always-read WORKFLOW_OPERATING_SYSTEM.md sections listed above. The reduced tier is a self-declared estimate of about 3,500 tokens for the trimmed subset above; it has not been independently re-measured by the same method, and should be read as an estimate rather than a fresh figure. The same reduced tier extends to the high-frequency execution commands implement-approved-slice and sync-task-state (v3 wave1 item D: the most-invoked commands pay the bootstrap most often; state-reconcile deliberately stays on the full tier, cross-artifact judgment needs the full guardrail context).
• Cache-amortized layer (ADR-0006): this bootstrap floor is a cache-amortized cost, not a per-command tax paid in full on every invocation. It sits in the prompt cache for the session and is paid at write cost once per cache TTL window, then at roughly 0.1x on cached reads inside that window. Account for it separately from any per-skill Load budget (the generated .claude/skills/<name>/SKILL.md body); the two are different layers and should not be summed into one figure.
• Session bootstrap reuse (skip-if-unchanged; v3 wave1 item D): WHEN this same conversation already performed this bootstrap read in an earlier turn that is still VISIBLE in the current context window AND WORKFLOW_OPERATING_SYSTEM.md has not changed since, the command MAY skip the re-read and cite the earlier one instead, emitting one Command transcript line: Bootstrap: reusing turn <N> read, WOS unchanged. This is a scoped exception to the context-budget re-fetch rule (wos/context-budget.md, "The re-fetch rule"), justified because the bootstrap sections are one large, static, byte-identical read repeated every turn rather than a variable tool result; the re-fetch rule still governs every other tool result without exception. VISIBLE means the bootstrap section text itself is still present and quotable in the window right now, not merely that the record of an earlier read exists. On a harness that clears, a tool result can be emptied while the record that the tool ran survives (ADR-0114); a command that finds only that record, without the section text still readable, has not satisfied VISIBLE and must re-read. Self-declared memory after a compaction never qualifies (re-read instead), and a stateless-per-turn harness is excluded. The auditable-skip rule applies: the transcript line is mandatory; a silent skip is invalid output.
• Read additional sections only when relevant to this command's role.
• Read the commands/ directory command inventory to ensure command names and availability are current.
• Align all routing recommendations and next-command suggestions with the current command set.
• Official next-command names only: every recommended next command (including the handoff Run now line) MUST be the basename of an existing commands/<name>.md file in this workflow repository. Never invent names.

Required inputs:

• active task folder path
• TASK_STATE.md (for the task arc: phase, last completed step, blockers, observations)
• the working session itself (what was attempted in this conversation, what failed, what was surprising, what was corrected)
• relevant task artifacts when present: SLICES/*.md, DECISIONS.md, IMPLEMENTATION_PLAN.md, PR_PACKAGE.md
• the existing LEARNINGS.md (read-only, for de-duplication; created from templates/LEARNINGS.md if absent)

Task repository files to update:

• projects/<client>__<project>/active/<task>/LEARNINGS.md (APPEND-ONLY; this command never edits or prunes existing entries, per ADR-0017 item 6)

Operating rules:

• Do not implement production code. Do not change any other task-memory file (no TASK_STATE.md edits here; route to /sync-task-state if state moved).
• Handoff: end with the adaptive ### Handoff block per WORKFLOW_OPERATING_SYSTEM.md ## Global output contract (Mode A compact or Mode B full).
• Append-only, read-only on history (ADR-0017). This command ONLY appends new entries. It MUST NOT edit, reword, reorder, compact, or prune any existing LEARNINGS.md entry. Compaction of LEARNINGS is out of scope for every command (ADR-0017 item 6); a harvest that rewrites history is invalid output. This command holds the Edit tool to append below the last entry, so the append-only invariant is enforced by this rule, not by tooling: before emitting, confirm no existing entry's bytes changed (only new lines were added at the end).
• A learning is reusable, not a task log. Admit an entry ONLY when the lesson generalizes beyond this one task: a failed approach and why it failed, a non-obvious constraint, a tool or environment gotcha, a sequence that worked when the obvious one did not. Reject one-off task status, decisions already recorded in DECISIONS.md, and restatements of the plan. When the session produced nothing durable, return a NO_OP rather than manufacturing a lesson (ceremony is the failure mode this rule prevents).
• Anchor every entry. Each proposed entry MUST anchor at the exact point it came from (file:line, a slice section header, a command name, or a timestamped TASK_STATE.md row) and follow templates/LEARNINGS.md ## Entry shape. An entry that is a retrospective summary with no anchor is disqualified, not appended (same bar slice-closure applies to inline learnings). Emit an optional Tags: line (comma-separated keywords) on each entry so rank-learnings.sh can surface it for a future task (ADR-0071).
• De-duplicate against existing entries. Before proposing, read the current LEARNINGS.md and drop any candidate already captured (the same lesson at the same anchor, comparing anchors case-insensitively and with surrounding whitespace normalized so a trivially reformatted anchor is still caught). Surface near-duplicates as "already captured" in the transcript rather than re-appending; LEARNINGS is cumulative, not a changelog of re-discoveries.
• Stay inside one task. Write only to the active task's LEARNINGS.md. A lesson that is genuinely cross-project belongs in USER_MEMORY.md (ADR-0016); name it in the output as a pointer for the user to promote, but do not write USER_MEMORY.md yourself. Likewise, a lesson whose subject is the workflow system's own contract is flagged as a candidate workflow-repo dogfood finding for the user to file in the workflow repository (problem-framing or task-init there, or capture-observation in an already-active workflow task); this command never writes outside the active task.
• Treat task-memory write policy per WORKFLOW_OPERATING_SYSTEM.md: PROPOSED in Ask mode, APPLIED only in Agent mode.
• Distinctness. capture-observation captures a single in-flight note verbatim without judgment; slice-closure captures the learnings of one slice as it closes; task-close is the terminal lifecycle move. This command is an on-demand, session-wide harvest that can run mid-task or at the end, and it judges what is durable before writing.

Required output:

1. A one-line read of whether the session produced durable lessons (or a NO_OP routing back to the prior work when nothing generalizes)
2. The candidate lessons found, each with its anchor and a one-line reason it generalizes
3. Which candidates were dropped as duplicates or one-off trivia, and why
4. Exact LEARNINGS.md append block (the new entries only, in templates/LEARNINGS.md shape), marked PROPOSED or APPLIED per editor mode
5. Any cross-project lesson flagged as a pointer to USER_MEMORY.md, and any workflow-contract lesson flagged as a candidate workflow-repo dogfood finding for the user to file in the workflow repository (neither written here)
6. Recommended next command
7. Recommended editor mode
8. Why that is the correct next step

Claim grounding (active epistemic humility)

Claim grounding (active epistemic humility). This block governs what you may assert and how you record it. It is keyed to the substrate section you are writing, not to which command is running, and it is INERT on any output that writes none of the claim-bearing sections below. Full contract and rationale: wos/active-epistemic-humility.md.

1. When this applies. This block fires ONLY while you are writing a claim-bearing substrate section: TASK_STATE.md ## Current known facts, ## Risks to watch, ## Observations, ## Active files in scope, ## Canonical decisions; DECISIONS.md ## Locked decisions; IMPLEMENTATION_PLAN.md ## Current gaps, ## Risks and mitigations; IMPACT_ANALYSIS.md; EXTERNAL_RESEARCH.md; REFERENCES.md; or any section whose content is a statement a later command or a human decision will act on. WHEN your output writes none of these, this block imposes nothing: skip it and proceed. This is the D-13 inert clause; a fully-grounded or claim-free output pays nothing.

2. The unit is the load-bearing claim. A load-bearing claim is one a downstream command or a human decision consumes. A passing aside is not load-bearing; a statement someone will act on is. Apply the rest of this block per load-bearing claim, not per sentence.

3. Ground it or abstain. Before you assert a load-bearing claim, trace it to the enumerable grounded set: a captured REFERENCES.md entry, a file read in this session, command output actually seen, or a passing deterministic gate. A claim supported only by model memory is OUTSIDE the grounded set, including when you are right, because that support is not observable. WHEN a load-bearing claim falls outside the set, do NOT assert it: either investigate until it is grounded, or abstain per rule 6.

4. Status records provenance, never confidence. WHERE you attach an epistemic status to a claim, the status names WHERE THE CLAIM CAME FROM: a REFERENCES.md entry title, a file path plus line, or the gate output it came from. It SHALL NOT express a degree of certainty. Do NOT add a confidence field, a numeric threshold, or a self-assessment prompt anywhere; a self-reported confidence signal is not a usable control signal (wos/active-epistemic-humility.md Part 1.3). A status whose referent slot is empty is read as UNKNOWN, not as a weak yes.

5. Persisted claims carry the status; chat-only claims carry it when they route. Every load-bearing claim you write into a task-memory artifact carries its provenance referent, and that referent travels with the claim so a later command reads it too; do not drop it at the write boundary. A load-bearing claim that appears only in a chat-turn output carries a status only when it crosses the grounding boundary and triggers a route (an abstention, an escalation).

6. Abstain as a routed continuation, never a bare refusal. WHEN you abstain, name the specific investigation that would settle the question AND route to the command that runs it (capture-references, code-locate, incident-triage, or the fitting one). A withholding that stalls the work is invalid output. Abstention is distinct from NO_OP: NO_OP means there is no work to do; abstention means there is work and the grounding to do it is missing.

7. An unfired gate is not evidence. The absence of a fired check does not mean grounding existed. Do not read silence here as a pass.

Standard output layout (required)

Produce the command output using this structure (English only):

Artifact changes

Follow ## Global output contract in WORKFLOW_OPERATING_SYSTEM.md for APPLIED / PROPOSED / SKIP rules.

Command transcript

Brief audit trail (max 4 lines; max 3 in no-op runs with NO_OP_TRACE).

Handoff

Use the adaptive ending format from WORKFLOW_OPERATING_SYSTEM.md ## Global output contract (Mode A compact or Mode B full per session state).

Definition of done (command output)

• Every appended entry is reusable beyond this task, anchored per templates/LEARNINGS.md ## Entry shape, and new (de-duplicated against existing LEARNINGS.md); an unanchored or one-off entry is invalid output.
• The run is append-only: no existing LEARNINGS.md entry is edited, reordered, or pruned, and no other task-memory file is touched.
• ### Artifact changes marks the LEARNINGS.md append as PROPOSED in Ask/Plan mode or APPLIED only in Agent mode; a session with nothing durable returns a NO_OP rather than a manufactured lesson.
• Output ends with a complete ### Handoff block per the adaptive format in WORKFLOW_OPERATING_SYSTEM.md ## Global output contract.
• Before declaring this output done, confirm it satisfies the shared Definition of done (command outputs) and Gate conditions in WORKFLOW_OPERATING_SYSTEM.md.

Quality bar: Optimize for a small number of high-signal, anchored, reusable lessons that make the next task start smarter, with zero rewriting of past entries and zero manufactured filler.