Skip to main content
Glama

load_trace

Idempotent

Load a Perfetto trace file to initialize analysis and receive a routing summary. Required before using other tools in this server.

Instructions

Load a Perfetto trace file for analysis and return a lightweight routing summary (trace type/profile, duration, platform, process/thread counts, capabilities, and recommended next tools). Every other tool operates on the trace set here.

Use when: starting any analysis session — call this first.

Don't use for: live trace capture (Perfetto records traces; perfetto-mcp-rs only reads the resulting file) or for streaming URLs (path must be a complete file on local disk).

Parameters: path is an absolute path to a Perfetto trace file (.pftrace, .perfetto-trace, .bin, or any other format trace_processor accepts — content-sniffed, not by extension). Calling again with a new path replaces the active trace; cached trace_processor_shell instances make repeat loads near-zero-cost unless the same path's metadata/content fingerprint changed since it was loaded.

Errors when: the file doesn't exist, isn't a valid Perfetto trace, or trace_processor_shell fails to parse it (corrupt trace, version mismatch). On first run only, also errors if the trace_processor_shell binary fails to download from the Perfetto LUCI bucket.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
pathYesAbsolute path to a Perfetto trace file (.pftrace, .perfetto-trace, .bin, or any other trace_processor-readable format — content-sniffed, not by extension).
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare idempotentHint=true and destructiveHint=false. Description adds valuable context: repeat loading behavior, caching, and error conditions, fully disclosing behavioral traits beyond what annotations provide.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Well-structured: purpose first, then usage guidelines, parameter details, and error conditions. Every sentence is informative and earns its place, with no redundancy or verbosity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple tool with one parameter and no output schema, the description covers all necessary aspects: purpose, when to use, parameter semantics, behavioral details, and error scenarios. It is fully self-contained.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with a description for `path`. The description further elaborates that paths are content-sniffed, not extension-based, adding meaning beyond the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'Load a Perfetto trace file for analysis and return a lightweight routing summary'. It specifies the resource (trace file) and distinguishes from sibling analysis tools by emphasizing that this setup call is prerequisite.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly advises 'Use when: starting any analysis session — call this first.' and 'Don't use for: live trace capture ... or streaming URLs', providing clear context, exclusions, and alternative.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Install Server

Other Tools

Latest Blog Posts

MCP directory API

We provide all the information about MCP servers via our MCP API.

curl -X GET 'https://glama.ai/api/mcp/v1/servers/tooluse-labs/perfetto-mcp-rs'

If you have feedback or need assistance with the MCP directory API, please join our Discord server