CtrlK
BlogDocsLog inGet started
Tessl Logo

exploring-apm-traces

Investigates distributed application performance using PostHog APM (OpenTelemetry span) data via MCP. Use when the user asks about service traces, slow HTTP/database spans, error spans, error-rate trends or spikes, latency distributions, trace IDs, or span attributes — not AI observability traces or product logs. Uses posthog:query-apm-spans, posthog:apm-trace-get, posthog:apm-spans-sparkline, posthog:apm-services-list, posthog:apm-attributes-list, and posthog:apm-attribute-values-list.

75

Quality

92%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide

SecuritybySnyk

Low

Low-risk findings worth noting

SKILL.md
Quality
Evals
Security

Quality

Content

85%

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

A highly actionable, well-structured body with executable examples, clear sequenced workflows, and appropriate one-level-deep bundle references. Its only weakness is mild repetition of a few key reminders (_posthogUrl, payload attributes) that slightly inflates length.

Suggestions

Consolidate the repeated "always include _posthogUrl" guidance into one canonical location (e.g., the UI-links section) and reference it from Step 1 and Tips rather than restating it three times.

Merge the recurring span-attributes-in-payload notes into a single authoritative explanation to reduce duplication across the investigation patterns and Tips.

Consider moving the per-tool gotchas (nanoseconds, status_code enum, kind enum) into references/spans-and-fields.md alongside the other enums to shorten the inline body.

DimensionReasoningScore

Conciseness

The body is dense and assumes Claude's competence (no "what is OpenTelemetry" padding), but several instructions are repeated — "always include the _posthogUrl" appears in Step 1, the UI-links section, and Tips, and the span-attributes-in-payload note recurs — so it could be tightened, matching the "mostly efficient but could be tightened" anchor rather than the lean top anchor.

2 / 3

Actionability

Guidance is copy-paste ready: exact JSON tool-call bodies, bash invocations with concrete env vars (SPAN=, SEARCH=, MAX_LEN=), and specific filterGroup examples — fully executable rather than descriptive.

3 / 3

Workflow Clarity

Multi-step processes are explicitly sequenced (Step 1 fetch → Step 2 parse) and each investigation pattern is a numbered checklist with confirm steps (e.g., re-running without the bad-set filter to confirm over-representation); this is a read-only skill so the destructive-op validation cap does not apply.

3 / 3

Progressive Disclosure

SKILL.md is an overview with well-signaled, one-level-deep references to a real references/spans-and-fields.md (schema/enums) and real scripts/ files, each surfaced via tool and script tables — clear navigation with no nested-reference chains.

3 / 3

Total

11

/

12

Passed

Description

100%

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, third-person description that states concrete capabilities, gives an explicit "Use when" trigger with natural user phrasings, and disambiguates from adjacent PostHog skills. It hits the top anchor on all four dimensions.

DimensionReasoningScore

Specificity

Names the concrete domain ("PostHog APM (OpenTelemetry span) data via MCP") and enumerates specific actions and targets ("slow HTTP/database spans, error spans, error-rate trends or spikes, latency distributions, trace IDs, or span attributes") plus the exact tools used, matching the "lists multiple specific concrete actions" anchor.

3 / 3

Completeness

It explicitly answers both what ("Investigates distributed application performance using PostHog APM...") and when ("Use when the user asks about..."), with an explicit trigger clause, so it is not capped at 2.

3 / 3

Trigger Term Quality

The "Use when the user asks about service traces, slow HTTP/database spans, error spans, error-rate trends or spikes, latency distributions" clause covers natural phrasings a user would actually say, matching the good-coverage anchor.

3 / 3

Distinctiveness Conflict Risk

It carves a clear niche (PostHog APM / OpenTelemetry traces) and explicitly excludes overlapping skills ("not AI observability traces or product logs"), making wrong-skill triggering unlikely.

3 / 3

Total

12

/

12

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.

Validation16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository
PostHog/posthog
Reviewed

Table of Contents

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.