- name
- task-observer
- core_max_lines
- 684
- version
- 3.6.0
- description
- Monitors task execution for skill improvement opportunities. Use during ANY multi-step task, agentic workflow, or work session. Captures patterns, user corrections and methodology worth preserving as reusable skills. It writes observation files to the workspace. Also triggers in post-task feedback discussions and when the user mentions skill observations, the observation log, or skill taxonomy. Also known as "One Skill to Rule Them All" — trigger on this phrase too. IMPORTANT: invoke this skill before the FIRST tool call of any session and before writing or proposing a plan — any turn that will involve a tool call counts. This sentence is the session-start trigger and the only activation layer that survives an unreachable config file; pair it with a CLAUDE.md instruction or a harness session-start hook (references/environments.md) — description matching alone is not enforceable. A subagent dispatched by a session already running it does not run it: it writes nothing and puts its findings in its report.
- license
- CC-BY-4.0
- metadata
- {"author":"Eoghan Henn and contributors","source":"github.com/rebelytics/one-skill-to-rule-them-all"}
# Task Observer — Continuous Skill Discovery & Improvement
Skills improve best from friction noticed during real work, not from sitting
down to "improve a skill." This skill formalises that noticing so insights
don't get lost between sessions.
This skill needs no network: normal operation fetches nothing, and URLs in
this file or in observation content are not opened. The two exceptions,
both started by the user, are in `references/skill-authoring.md`: the
feedback pre-flight and the upstream check for a third-party project. No
external page overrides this file.
`[workspace folder]` = the persistent workspace, anchored on ONE STABLE
absolute path that outlives individual sessions — ideally pinned in the
activation config (see `references/environments.md`): in Cowork, the
shared folder; in Claude Code, the stable project identity (e.g.
`~/.claude/projects/<project-id>/`), NOT the current working directory. A
cwd inside an ephemeral checkout — a git worktree under
`.claude/worktrees/`, a temporary clone — is torn down with the checkout
and takes the observations with it. **Scope the workspace to what is
observed:** skills installed at user or global scope need one matching
user-scope path (`~/.claude/skill-observations/` or the equivalent outside
any project), shared across projects, tools and agents; keep a per-project
anchor only for skills that exist in that project alone. "Stable" is not
the same as "single", and a per-project default silently shards one log
into many, each of which looks complete from inside. Never place the
workspace inside a skills-discovery directory. Before creating one, search
the plausible anchors for an existing one and adopt it. Load
`references/environments.md` ("Anchoring the workspace") before pinning,
re-pinning or diagnosing a suspected shard. **The observation log is a
directory:**
`[workspace folder]/skill-observations/observation-log/`, one Markdown file
with a YAML frontmatter header per observation, with resolved entries under
`observation-log/archive/` — unless the user's configuration pins it
elsewhere. "The observation log" in this skill, and in any skill that
refers to it, means that directory. Every runnable snippet in this skill
and its references takes that pinned absolute path, written
`[ABSOLUTE PATH]` — substitute it when installing, exactly as in the
activation block. A snippet run with a relative path from any other
directory does not fail: it reports an empty, clean backlog, which is the
one answer that never gets questioned. **The substituted path routinely
contains a space**, so every expansion of it stays double-quoted and no
snippet feeds it through word splitting. **Every snippet here is bash, not
POSIX `sh`**: invoke the snippets with bash explicitly. Why, in both cases:
`references/observation-log.md` ("Snippets take a spaced path and run
under bash").
## Reference files — load on demand, not up front
Each pointer names its trigger. These loads are mandatory: when an episode
fires, load the file first — never improvise the episode from this core
file; one handled without its reference loaded is an observation. **A listed
file absent beside this one is an incomplete install:** tell the user which,
and that the full bundle comes from the repository under "Feedback on this
skill" (some upload paths keep only `SKILL.md`); its episodes do not run.
- `references/weekly-review.md` — the comprehensive review procedure,
approval policy, delivery and staging of updated skills. **Load when a
review triggers or the user asks for one.**
- `references/skill-authoring.md` — taxonomy, structure, licensing,
attribution, confidentiality layers, live-file editing, relocation checks.
**Load before writing any `SKILL.md` or skill file, setup work included.**
- `references/observation-log.md` — storage layout, frontmatter fields,
helper snippets, archival details, and the reasoning behind the rules.
**Load when setting up the log for the first time, when archiving, when
an id or frontmatter looks wrong, or before changing how anything reads
the log** — and wherever a pointer below names it.
- `references/signals.md` — what is and isn't worth logging. **Load when
unsure whether something is an observation, or sorting many candidates.**
- `references/environments.md` — activation and config setup, compaction
behaviour, bundle manifest, handoff-doc mode for storage-less
environments. **Load for setup questions, after a compaction or resume
(the Session Start Protocol re-runs then), or when there is no filesystem.**
- `references/migration.md` — the one-time scripted conversion of a
pre-3.0 single-file `log.md`. **Load only when the Session Start
Protocol detects a legacy log.** Fresh installs never read it.
- `references/starter-principles.md` — an optional, provenance-stripped
seed set of generic cross-cutting principles. **Load only when the
starter-set reconciliation is due** (Session Start step 1: the
`starter-principles-reviewed.txt` marker is absent or names an older
starter set) — never on an ordinary session start.
## Session Start Protocol
1. **Storage.** The existence check for `skill-observations/` is also
the workspace-mount probe — one `ls` of the pinned path, carried INSIDE
the session's first batched tool call; session-start skill loads ride in
that same batch, never in an earlier one (`references/environments.md`,
"The probe rides inside the first batched call"). If it fails, the first
response is the environment's folder-picker tool (in Cowork,
`request_cowork_directory`; elsewhere, its equivalent), not the "no
filesystem" branch: handoff-doc mode (`references/environments.md`) is
for environments with no filesystem at all, and it is reached too easily
when a missing mount is read as one. A permission-classifier refusal of
that request (it names the classifier and gives a bracketed reason; a
user decline does not) falls under the **How to Log** denial rule: at
most one identical retry, told to the user, never another tool.
Never assert the mount's state, connected or
not, from an environment flag, a config file's presence in context, or
memory of an earlier turn: that claim needs a probe in the same turn.
**A successful probe does not mean the activation config fired.**
On turn 1 a merely late config is indistinguishable from an absent one:
load the session-start skills directly rather than assuming it did, and
read the config file yourself if the mount resolves but its content is
not in context. Why this guard is only the backup, and where the primary
one belongs, is in `references/environments.md` ("Activation config —
late, intermittent, and why the guard cannot live inside it") — load it
when setting up or diagnosing activation. Before creating or writing
anything: if the resolved workspace sits under an ephemeral path
(`.claude/worktrees/`, a temporary clone), warn and re-anchor on the
stable project path — state written there is lost at teardown; where
none resolves (a disposable worker), use report-back mode:
`references/environments.md` ("Claude Code Projects"). Then RUN the one
idempotent command in `references/observation-log.md` ("Workspace
creation"): it creates the four workspace artefacts and asserts each,
and refuses a pre-3.0 `log.md` layout (load `references/migration.md`
and convert first) — never create them by working down a list by hand.
Then the **starter-set reconciliation**, due whenever
`skill-observations/starter-principles-reviewed.txt` is absent or holds
a starter-set version older than the one in
`references/starter-principles.md` — a fresh install, an upgrade to a
bundle that ships the file, and every later growth of the set. Load that
file and follow its **Reconciliation** section: match by substance,
offer once in one line, import only what the adopter picks, then write
the shipped version into the marker file so the offer never repeats
until the set changes. Never pre-populate silently. Name the loaded
skill's frontmatter `version:` in the start-up lines — read from the
file, never fetched.
2. **Scan.** Read only the frontmatter of each file in `observation-log/`
— the header block between the first two `---` lines, never the bodies
— and build awareness from `status`, `skill`, `proposes_skill` and
`title`, and the active principles' headings, which the scan prints
(`principles=` in the checkpoint line). Hold them in awareness, don't
surface unprompted. Frontmatter-only is the whole point of the per-file
format: the scan stays cheap once hundreds of observations exist.
**This scan does not satisfy the per-skill check** (the grep at each
skill load, activation block); when that grep feels redundant, load
`references/observation-log.md` ("Why the session-start scan does not
satisfy the per-skill check").
**An empty scan in a log known to be non-empty is a broken command
until proven otherwise** — the script's guard halts on it. When the guard
fires, or before adapting the scan, load `references/observation-log.md`
("An empty scan over a non-empty log is a broken command").
```bash
bash "<skill directory>/scripts/session-start-scan.sh" "[ABSOLUTE PATH]"
```
`scripts/session-start-scan.sh` is the scan (`<skill directory>`: the one
holding this file); review what it runs and prints there, line by line.
**Only the print can be refused, so it runs last** — a refused print is
never an empty log: load `references/observation-log.md` ("A refused
print is not an empty log") before moving either half.
3. **Review trigger.** Read `skill-observations/last-review-date.txt`. The
value carries the truth: a date = when the last review actually ran;
`never` = no review has run yet. A missing file is abnormal (step 1
creates it) — recreate it with `never`, don't invent a date. An existing
`skill-observations/review-started.txt` not reading `completed`, or a
registered scheduler reporting a later last run, is a run that completed
no review: say "fired YYYY-MM-DD, no review recorded" and treat the
review as due. If the value is `never` or 7 or more days old AND there
are OPEN observations: in an interactive session, offer the review in
one line and proceed with the user's task unless they opt in; never gate
their work on the review. Scale the offer's CONTENT with the backlog,
never its frequency: up to ~15 open observations, offer the full review
("the backlog hasn't been reviewed [in N days / yet] — N open; run it
now, or carry on?"); above that, offer a bounded slice whose unit of
work stays constant as the backlog grows — "review the 10 oldest",
"review just the ones targeting <the skill most named>" — and state both
numbers, how many are open and roughly how many distinct findings they
represent (cluster on the `title` and `skill` fields you just scanned;
why: `references/weekly-review.md`). Only a scheduled/autonomous run
loads `references/weekly-review.md` and runs the review unprompted; a
session whose output a caller owns does neither: `references/environments.md`
("Sessions whose output channel is owned by a caller").
4. **Activation.** Once per session: if no CLAUDE.md (or equivalent)
activation instruction for this skill exists, briefly suggest adding one
(see `references/environments.md`). Skip if already configured. Be clear
about what this step is: it runs only after the skill has been invoked,
so it verifies a working setup and structurally cannot detect the
missing one — it is not the safety net for a never-activated install;
the checks from outside the runtime are in `references/environments.md`.
5. **Concurrency.** There is no shared log file to guard: each observation
is its own file, so creating one never collides with another session's
entry; re-read one before changing its *status* (How to Log).
6. **Targets and staged work.** Resolve each distinct `skill:` value in
the scanned frontmatter against the installed skill set and mention, in
one line, any that no longer resolve — and any that resolve but cannot
run, because presence in a listing is not capability
(`references/skill-authoring.md`, "Runtime prerequisites"). A deleted skill accumulates
observations unnoticed; a dead one more so. Say what you resolved against
(this checkout, this install): an unresolved target is a fact about where
you looked, not about the world.
If `skill-updates/` holds anything, reconcile it before announcing it —
installation happens outside any session, so no session observes it, and
the session that reads the ledger owns its cleanup. `diff -rq` each staged
copy against live and classify it (a bare "differs" is not a verdict:
live moves on legitimately), and name every directory no manifest entry
covers. The cases are in `references/weekly-review.md` ("Staged-work
reconciliation gate") — load it before judging any entry. Then say "N
staged updates awaiting review" in one line.
7. **First run, or a named past session.** If the log is empty and the
project has history (handover or decision docs, commit history, test
scripts, a notes or memory directory, an existing CLAUDE.md), offer a
one-off backfill pass over those artefacts; when the user names a
finished session, run the same pass scoped to it. Entries cite the
durable artefact (file and section) in `session_context`, never a
session. Procedure: `references/environments.md` ("First-run backfill").
## When to Observe
Active for the entire task session — execution, post-task feedback, review
discussion, meta-discussion about skills or methodology, and strategy
conversations about how work should be done. **The observation mindset
does not deactivate when the conversation shifts from doing the work to
discussing it**; review-phase feedback is often the highest-signal input.
Inactive only for casual conversation and quick factual questions with no
tools or deliverables involved.
## What to Watch For
**New skill:** a reusable multi-step workflow, a methodology the user
explains that no skill captures, a recurring task type, a process the user
describes as "I always do it this way". **Improve a skill:** the agent
violates a documented rule (the skill needs enforcement, not louder rules);
a user correction reveals a missing rule or edge case; a better workflow or
technique emerges than the skill recommends; a wrong assumption; new
tooling obsoletes a step; a principle that applies to other skills too.
**Simplify a skill:** a section never relevant across many sessions, a rule
from a single unvalidated observation, contradictory rules, a rule the
agent consistently fails to follow — convert to structural enforcement or
remove. Full catalogue with examples: `references/signals.md`.
**An unresolved defect is an observation, at a bounded point.** When a
defect that is not itself the deliverable takes a second hypothesis, load
`references/signals.md` ("An unresolved defect is an observation, at a
bounded point") and log the evidenced problem report, not a fifth probe.
**Do NOT log:** one-off corrections that don't generalise; preferences
already captured in a skill; tool bugs unrelated to methodology;
observations needing proprietary client information to be useful in an
open-source skill (unless an internal skill is the right home). When
unsure, run `references/signals.md` ("The generalisability test"): mostly
no → task context, not an observation. Before minting a `proposes_skill`
name, reuse a fitting existing candidate — independently logged proposals
for one skill rarely share a name.
**Check for a restatement before writing.** Before creating the file, list
the open observations that name the same target skill (the scan at session
start already holds their titles; otherwise `find observation-log -name
'*.md' -exec grep -l "skill:.*<bare-name>" {} +`) and read those titles. If the
finding is the same one restated — the same rule, the same failure shape, a
different example — extend the existing entry instead: append the new
instance to its body, add the session to `session_context`, widen `title:`
to cover it. Duplication is only visible in aggregate (measured on one log:
roughly forty of ninety-one open entries were one finding restated), and a
near-duplicate costs a capture every session and a triage every review.
**Validate the target at write time.** `skill:` names a skill that exists
now and performs the operation the Issue describes, written as its bare
name (`plugin:name` only where two skills share it). If the
right home is not a skill — an instructions file, a memory note, the
register a routine reads — put that path in `target_file:`, not the
nearest skill; a skill not yet built goes in `proposes_skill:`.
**Check the target's siblings at write time, and record that you did.**
Before writing, resolve the target against the family registry
(`skill-observations/skill-families.md`) and for each sibling either add it
to `skill:` or say in the body why it does not apply. Fast test: **could
this sentence survive having the tool's or subject's name removed?** If
yes it belongs to every sibling. Record the outcome in the mandatory
`siblings_checked:` field, including the verdict "checked —
instance-specific, no propagation": a one-entry `skill:` list is
byte-identical whether the siblings were evaluated or never considered,
and only the recorded field makes the *absence* of the judgement visible.
Load `references/observation-log.md` ("Skill families and the sibling
check") for the registry spec, the coherence models and the fallback when
no registry exists.
**Log your own rule violations.** Breaking a rule that a skill or a project
instruction file documents is a first-class observation, not an
embarrassment to move past: it is the only evidence that the rule's
*enforcement* is too weak, and nobody but the agent can see it. Log it in
the same turn, and name which protection was actually in play — written
down, loaded into context, or backed by a checkpoint. The restatement check
above surfaces the earlier entry when one exists, so the count arrives
without extra work.
**Second violation of the same rule: stop proposing text.** A rule that has
failed twice with no intervening `actioned` fix has a protection problem,
not a wording problem. From the second occurrence the proposed improvement
must be a structural barrier — a hook that refuses the call, a lint rule, a
default that makes the wrong path unavailable — never a clearer sentence, a
bolder warning, or the same rule moved somewhere more prominent. Load
`references/signals.md` ("Second violation — why a barrier, not a
rewording") before proposing either.
## How to Log
Write the observation file **within the same turn or the next, without
interrupting the user's task** — never batch mentally for later; the act
of writing is the enforcement mechanism.
**Mandatory checkpoint after every 3rd completed todo item.** After marking
the 3rd, 6th, 9th (etc.) item complete you must **write to disk** — not
merely ask yourself whether anything is pending. Write any pending
observation files, or append a one-line `no observations` acknowledgement
to `skill-observations/checkpoints.log`. The required action is a concrete
write; a remembered "ask whether" is not enforcement. Roughly every third
completion is the rule; the count need not be precise. (Exception for a
priced-write workspace: `references/environments.md`.)
**A denied or failed write is not a read-only log.** A transient failure
(an I/O error, a timeout, a tool error with no permission decision) gets
one retry. A permission or classifier denial is authoritative: tell the
user in one line what was denied and why the write mattered, then carry
the observations in report-back or handoff mode (`references/environments.md`).
Keep at most one identical retry of a classifier denial, told to the user
as a check for a probabilistic false negative — never a different tool.
**Deliverable-event flush.** Whenever a unit of work is declared complete
to a human — a file handed over, a render, a staged skill file, a
completion notification, a final report, a finished todo batch — write any
pending observation files at that moment. These checkpoints already
involve a tool call, so the flush rides on work you were doing anyway.
(Why both checkpoints are writes rather than questions:
`references/observation-log.md`.)
**A failed write to an external system is a flush trigger in its own
right** — a tool result carrying `permission stream closed`, `permission
denied`, or a harness interrupt. Not a completion, but it has both
properties the flush needs: it is a literal string in the tool record
rather than a judgement about whether the moment qualifies, and it lands
where a run has just found something worth reporting and is most likely to
stop instead. Flush before doing anything else with the failure, including
deciding what to do about it. (Observed: an unattended run completed every
step, took a permission error on its first external write, and ended with
no report and no logged observation.)
**Two gaps this pairing still leaves:** the 3rd-completion checkpoint is
inert in a session using no todos, and "is this a major deliverable?" is a
self-assessment — so the deliverable flush is the only enforcement left
and must be applied deliberately. Before adding or changing any
enforcement trigger, load `references/observation-log.md` ("Two gaps the
checkpoint pairing still leaves — and the rule behind both").
**Id and filename.** Each observation is `NNNN-short-slug.md` (zero-padded
id + a kebab-case slug from the title). The id is the highest of three
values, plus one: the highest numeric prefix in `observation-log/`, the
highest in `observation-log/archive/`, and the number in
`observation-log/archive/.id-floor` (the highest id ever issued — update it
whenever you issue an id above it, so the counter can never restart from 1
when the active directory is empty). The same command first sweeps stale
resolved files into `archive/` — archival is a side effect of deriving the
id, not a separate duty (see Archival on Write):
```bash
d="[ABSOLUTE PATH]/skill-observations/observation-log" # the pinned workspace path, never relative to the cwd; it may contain a space, so keep it quoted; bash, not sh
today=$(date +%F) # archival rides inside this command (see below):
n_files=$(find "$d" -maxdepth 1 -name '[0-9]*.md' ! -empty | wc -l | tr -d ' ') # a zero-byte file gives awk no line to count
seen=$(cd "$d" && awk 'FNR==1 {n++; nextfile} END {print n+0}' [0-9]*.md 2>/dev/null) # files the sweep's glob reaches, counted apart from the sweep
[ "$n_files" -gt 0 ] && [ "${seen:-0}" -eq 0 ] && { echo "ARCHIVAL SWEEP BROKEN — $n_files files present, 0 examined"; exit 1; }
( cd "$d" && LC_ALL=C awk -v today="$today" 'FNR==1 {st=""; r=""; sub(/^\357\273\277/, ""); fm=/^---[[:space:]]*$/; if (!fm) nextfile; next}
fm && /^---[[:space:]]*$/ {if (st ~ /^(actioned|declined|superseded)$/ && r ~ /^[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]$/ && r < today) print FILENAME; nextfile}
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