Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add mthines/agent-skills --skill playwright-trace-analyzergit clone --depth 1 https://github.com/mthines/agent-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/mthines/agent-skills/playwright-trace-analyzer)<a href="https://agentmods.dev/skills/mthines/agent-skills/playwright-trace-analyzer"><img src="https://agentmods.dev/badge/skills/mthines/agent-skills/playwright-trace-analyzer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/mthines/agent-skills/playwright-trace-analyzer"><img src="https://agentmods.dev/badge/skills/mthines/agent-skills/playwright-trace-analyzer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 6 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Prompt Injection · line 120 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
- medium Prompt Injection · line 95 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
- medium Prompt Injection · line 98 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
- medium Prompt Injection · line 101 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
- medium Prompt Injection · line 102 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
- medium Excessive Agency · line 165 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00077 | $0.02735 |
| Opus 5.5 | $0.00031 | $0.01094 |
| Sonnet 5.5 | $0.00015 | $0.00547 |
| Haiku 4.5 | $0.00008 | $0.00274 |
Grade A, and why
playwright-trace-analyzer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 234 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Playwright Trace Analyzer
Turn a Playwright trace.zip into a ranked, evidence-backed report of
flakes, slow steps, and root causes.
Index file. Detailed extraction rules, analysis playbooks, and report templates live under
rules/,references/, andtemplates/. Load only what the current phase needs — the body ofSKILL.mdis a thin orchestrator.
Inputs
The user passes one or more of:
| Input | Detection signal |
|---|---|
| GitHub Actions run URL | Matches https://github.com/<owner>/<repo>/actions/runs/<id> — fetch artifacts via gh run download |
trace.zip archive |
Magic bytes 50 4b 03 04; entries include trace.trace, trace.network, *.png, resources/ |
| Unpacked trace directory | Contains trace.trace + trace.network (NDJSON) and a resources/ subdir |
Single trace.trace JSONL stream |
NDJSON; each line has type, callId, startTime, params (e.g. before, action, after) |
Single trace.network JSONL stream |
NDJSON; entries with type: "resource-snapshot" or requestEvent / responseEvent |
report.json (Playwright reporter) |
Top-level config, suites, stats; complementary, never authoritative for timing |
If the user passes a report.json plus a trace.zip, treat the report as
a high-level test status map and the trace as the source of truth for
timing and network data.
If a test-results/ directory is passed, scan for the most recent
trace.zip per failed test and process them in order of failure recency.
See rules/input-detection.md for the
precise detection logic and unpack recipe.
Workflow
Six phases. Do not skip a gate.
| Phase | Name | Rule file | Gate |
|---|---|---|---|
| 0 | Intake | rules/input-detection.md |
Format detected, archive unpacked, trace.trace + trace.network parseable |
| 1 | Measurement frame | rules/measurement-methodology.md |
Failure mode named (timeout, assertion, error, slow-but-passing) and primary metric chosen (action ms, total wall-clock, request count) |
| 2 | Hotspot extraction | rules/action-timing.md, rules/network-analysis.md, rules/console-and-errors.md |
Top-N slow actions, top-N slow requests, error/console list — all with concrete numbers |
| 3 | Root-cause | rules/flake-diagnosis.md |
Each hotspot mapped to a code-level cause (selector, locator, network call, app event) with file path or line where possible |
| 4 | Confidence gate | rules/confidence-loop.md |
/confidence analysis ≥ 90% — else iterate (max 2 deep-dives) |
| 5 | Fix plan | templates/analysis-report.md |
Report written with ranked fixes, expected impact, and verification plan |
What ships with it
14 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- references/flake-patterns.md 6.4 KB
- references/performance-patterns.md 3.4 KB
- rules/action-timing.md 6.7 KB
- rules/confidence-loop.md 3.9 KB
- rules/console-and-errors.md 3.9 KB
- rules/flake-diagnosis.md 6.0 KB
- rules/input-detection.md 11 KB
- rules/measurement-methodology.md 5.1 KB
- rules/network-analysis.md 5.5 KB
- scripts/fetch-gh-run.mjs 8.4 KB runs code
- scripts/trace-diff.mjs 5.2 KB runs code
- scripts/trace-extract.mjs 7.6 KB runs code
- scripts/trace-summary.mjs 4.4 KB runs code
- templates/analysis-report.md 4.4 KB
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago Changed · -9 lines · -155 tokens per session b31467f65617
- 1mo ago First seen · 243 lines · 232 tokens per session scan A 997bbf6a3cd2
playwright-trace-analyzer is a skill published in the GitHub repository mthines/agent-skills (20 stars, last pushed yesterday), licensed MIT. It adds 77 tokens to every session and 2,735 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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