perf_evlist

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

With no annotations, the description carries the behavioral burden. It discloses the output format ('one event per line'), the data shown (name, type, config, sampling settings), and states there are no prerequisites. While it doesn't explicitly say 'read-only,' the verb 'List' and absence of mutation language make the behavior clear.

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

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

Every sentence earns its place: purpose, usage, parameter notes, output format, and prerequisites are covered in a short, front-loaded structure with no fluff.

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

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

For a simple list tool with six parameters, an output schema, and no annotations, the description covers purpose, usage, key parameters, output, and prerequisites. It is complete enough for an agent to invoke correctly without additional context.

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

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

All six parameters have schema descriptions (100% coverage), and the description adds extra guidance for freq, group, and verbose by explaining what each flag enables (e.g., 'verbose=1 for full perf_event_attr details'). This exceeds the baseline for a fully-schema-covered tool, though force and trace_fields aren't mentioned.

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

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

Description opens with a specific verb-resource pair: 'List events in a perf.data file.' It also differentiates itself from sibling perf tools by stating 'Always call this first to understand what was recorded before using other tools,' making its role in the workflow explicit.

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

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

Provides clear context: 'Always call this first' and 'No prerequisites — works on any perf.data.' It does not name an alternative tool for specific scenarios, but the 'first before other tools' instruction gives unambiguous usage timing.

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