Perfetto Skills

This directory holds a single skill: model-agnostic instructions that teach an AI agent how to do something useful with Perfetto. A skill is how Perfetto and the teams that use it encode the knowledge an expert would share when sitting next to a colleague — what to look at, which tables to query, what good queries look like, and how to interpret the results.

The format follows the Agent Skills convention: a skill is a directory containing a SKILL.md with YAML frontmatter (name, description) and a markdown body. Any tool that implements the convention — Claude Code, Gemini CLI, OpenAI Codex — can load it.

This is part of the ecosystem described in RFC-0025: AI in Perfetto and RFC-0026.

One skill, a router, and reusable files

Everything Perfetto ships is consolidated into one skill, ai/skills/perfetto/. Its entry point is a lean router; the actual knowledge lives in reference and workflow files the router dispatches to and loads on demand. This keeps a single, broad description in the agent's context budget instead of many sibling skills competing to match, and lets each piece be loaded only when the task needs it.

ai/skills/perfetto/
├── SKILL-template.md            # the router (see below — NOT named SKILL.md)
├── infra-references/
│   └── querying.md              # how to run trace_processor + PerfettoSQL
├── environment-references/
│   └── setup.md                 # $SKILL_ROOT + the bundled trace_processor
└── workflows/
    └── android_memory/
        ├── heap_dump.md
        ├── heap_dump_cluster.md
        ├── heap_dump_caching_optimizer.md
        └── scripts/             # SQL/Python shipped with these workflows

Three kinds of file:

• workflows/<domain>/*.md — entry points the router dispatches to: domain-specific guided investigations (a heap dump on Android, jank on Chrome, …). Group related workflows in a <domain>/ subfolder. A workflow is self-contained — it carries its own queries and any helper scripts under a sibling scripts/ dir.
• infra-references/*.md — domain-agnostic mechanics a workflow (or an ad-hoc request) pulls in: how to query a trace, etc.
• environment-references/*.md — environment setup: what to set $SKILL_ROOT to and how to invoke the bundled trace_processor.

The source tree is a build input, not a drop-in

Unlike a normal Agent Skill, this tree is not directly loadable. Two source-only conventions mean it has to pass through the bundler (tools/release/build_ai_agents.py) before any agent can load it:

1. SKILL-template.md, not SKILL.md. The router is named so a discovery layer scanning for SKILL.md will not pick up the unassembled source tree. The bundler renames it to SKILL.md.
2. No bin/trace_processor in source. The setup doc points every trace_processor invocation at $SKILL_ROOT/bin/trace_processor, but that wrapper is not checked in here — the bundler copies it in from tools/trace_processor at build time, so every install (plugin or fallback) carries a working binary inside the skill.

Every agent gets the identical assembled skill. See ai/extensions/README.md for how the assembled bundle reaches end users.

Reference other files by $SKILL_ROOT-anchored path

Every path a file mentions — links to other skill files, and the helper scripts a workflow runs — is written as $SKILL_ROOT/<path>, where <path> is relative to the skill root (the directory holding SKILL.md) and never relative to the file doing the referencing. So from workflows/android_memory/heap_dump.md:

follow `$SKILL_ROOT/infra-references/querying.md` first, then come back here.

Not ../../infra-references/querying.md (file-relative), and not a bare infra-references/querying.md either. Likewise a helper script is $SKILL_ROOT/workflows/android_memory/scripts/cluster_paths.py, and a trace_processor invocation spells the full path:

trace_processor query --query-file \
  $SKILL_ROOT/workflows/android_memory/scripts/triage_dominator_path.sql TRACE_FILE

$SKILL_ROOT is the one anchor that makes this unambiguous. The skill is loaded from a plugin/install directory that is not the agent's working directory (that's the user's workspace, where the trace lives), so a bare relative path would resolve against the wrong place. environment-references/setup.md — the always-required first read — tells the agent to set $SKILL_ROOT to the directory it loaded SKILL.md from, and to put the bundled $SKILL_ROOT/bin on the session's PATH so bare trace_processor commands work. Once it's set, every $SKILL_ROOT/... path resolves the same way regardless of the working directory, whether the agent is opening a referenced markdown file or passing a script to the shell.

The router (SKILL-template.md) sits at the skill root, so its $SKILL_ROOT/... links have no intermediate ../; every other file speaks the same path language. A file can move between subfolders without rewriting its outgoing links (only references to it change).

Authoring

• Portability. A file will be read by tools without access to this checkout. Never use repo-relative paths like src/trace_processor/... or refer to tools/... scripts; assume the reader only has trace_processor and a trace. Link to absolute URLs on perfetto.dev/docs.
• The router (SKILL-template.md) stays minimal: match broad in its description, then route. When you add a workflow, add one row to its table. Keep it short.
• Add a workflow as workflows/<domain>/<name>.md, with any scripts in a sibling scripts/. Write the body in the imperative, like a runbook. Pull in $SKILL_ROOT/infra-references/querying.md (anchored path, as above) rather than re-explaining how to query.
• Test against a real trace before checking in. Files that have never been run end up with broken syntax and wrong column names.