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replay-oriented-instrumentation

Instruments programs to record execution information for deterministic replay debugging. Use when debugging hard-to-reproduce bugs (race conditions, timing issues, intermittent failures, heisenbugs), reproducing production failures, or analyzing complex execution sequences. Records non-deterministic events (I/O, threading, randomness, time) to enable exact replay of program executions. Supports Python, JavaScript, Java, and C/C++ with both custom instrumentation and existing replay tools.

67

Quality

84%

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SKILL.md
Quality
Evals
Security

Quality

Content

67%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A well-structured, code-rich skill with a clear six-step workflow, validation checkpoints, and real one-level-deep reference files. The main weaknesses are padded generic-advice sections that duplicate references or state the obvious, and a few code fragments that are not fully copy-paste ready.

Suggestions

Trim or move the generic advice in 'Recording Strategies' and 'Tips' (e.g., 'Compress logs', 'Deduplicate repeated values', 'Start simple') — Claude can derive these; keep only replay-specific guidance such as 'Test replay early' and 'Automate verification'.

Cut the 'Core Concept' explanation of record/replay basics and the 'Common sources' bullet list, which duplicates references/non-determinism.md; a one-line pointer to that reference suffices.

Add an error-recovery step to the workflow for when verify_replay reports a mismatch (e.g., 'if replay diverges, check for unrecorded non-determinism sources — signals, environment variables, hash seeding') to complete the feedback loop.

Make the first JavaScript/Nock example fully round-trip (connect 'nock.recorder.play()' output to 'nock.define()' as the Scenario 2 example does) and note the prerequisite 'log_event' helper for the C RECORD_CALL macro.

DimensionReasoningScore

Conciseness

The body is mostly efficient and code-first, but several sections pad with what Claude already knows: 'Core Concept' explains that 'Deterministic replay works by: Recording... Replaying...', the 'Common sources' bullets ('File reads, network requests, user input') duplicate references/non-determinism.md, and 'Recording Strategies'/'Tips' offer generic advice like 'Compress logs', 'Deduplicate repeated values', and 'Start simple'. This matches the 3 anchor (some unnecessary explanation that could be tightened) rather than 2, since the majority of the body is concrete code that earns its tokens.

3 / 5

Actionability

Concrete, mostly executable guidance throughout: the Python 'ReplayRecorder' class, 'rr record python script.py' / 'rr replay -d gdb' with '(gdb) reverse-continue', the AspectJ '@Around("execution(* java.io..*(..))")' aspect, and a runnable 'verify_replay' function. It falls short of the 5 anchor because some examples are fragments — the first Nock snippet never connects 'nock.recorder.play()' output to 'nock.define' for replay, and the C 'RECORD_CALL' macro assumes an undefined 'log_event' — leaving minor gaps.

4 / 5

Workflow Clarity

The six-step workflow (Identify Non-Determinism Sources through Debug with Replay) is clearly sequenced with explicit checkpoints ('Verify recording completed successfully', 'Verify replay matches original execution') and a dedicated 'Replay Verification' section with code. Not 5 because there is no error-recovery feedback loop: nothing says what to do when 'REPLAY MISMATCH!' occurs (e.g., hunt for unrecorded non-determinism sources), which is the hardest part of the process.

4 / 5

Progressive Disclosure

Good structure: all three referenced files actually exist (references/non-determinism.md, python-replay.md, replay-tools.md), are one level deep, and are clearly signaled both inline ('See [references/replay-tools.md](references/replay-tools.md)') and in a described 'References' section. Not 5 because the ~360-line body inlines substantial material — three full 'Common Scenarios' implementations plus generic strategy lists — that could partly live in the references.

4 / 5

Total

15

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20

Passed

Description

92%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description: third-person voice, explicit what and when clauses, concrete enumeration of recorded event types and supported languages. The only gap is a few missing natural trigger synonyms (notably 'flaky tests'), which keeps trigger term quality at 4 rather than 5.

DimensionReasoningScore

Specificity

Concrete actions are named throughout: 'Instruments programs to record execution information for deterministic replay debugging', 'Records non-deterministic events (I/O, threading, randomness, time) to enable exact replay of program executions', with scope detailed down to 'Supports Python, JavaScript, Java, and C/C++ with both custom instrumentation and existing replay tools'. This matches the 5 anchor (multiple specific concrete actions, comprehensive coverage); it is not 4 because there are no material gaps in the coverage it claims.

5 / 5

Completeness

It explicitly answers both what ('Instruments programs to record execution information for deterministic replay debugging... Records non-deterministic events (I/O, threading, randomness, time)') and when ('Use when debugging hard-to-reproduce bugs (race conditions, timing issues, intermittent failures, heisenbugs), reproducing production failures, or analyzing complex execution sequences') with concrete trigger phrases. This matches the 5 anchor; it is not 4 because the 'when' clause is already explicit and specific.

5 / 5

Trigger Term Quality

Strong natural trigger phrases users would actually say: 'race conditions', 'timing issues', 'intermittent failures', 'heisenbugs', 'reproducing production failures'. It falls short of the 5 anchor because a few common natural terms are missing — notably 'flaky tests' (the most common user phrasing for this problem), 'record and replay', and 'time-travel debugging'.

4 / 5

Distinctiveness Conflict Risk

It occupies a clear niche — deterministic replay instrumentation — with distinct triggers ('heisenbugs', 'reproducing production failures', 'deterministic replay debugging') that are unlikely to fire for general debugging or profiling skills. Matches the 5 anchor; not 4 because the replay-specific framing leaves minimal overlap risk with adjacent skills.

5 / 5

Total

19

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20

Passed

Validation

100%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository

ArabelaTso/Skills-4-SE

Path

skills/replay-oriented-instrumentation/SKILL.md

Reviewed

Table of Contents

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