perf_inject

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

With no annotations, the description carries the full burden. It discloses that the tool writes a new perf.data file and returns path and size, and it explains the semantics of the itrace values. However, it does not mention side effects like overwriting existing output or the meaning of the force flag, though these are present in the schema.

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?

The description is efficient and well-structured: it leads with the core purpose, then a usage note, then a key-parameter list, and finally the output. Each sentence contributes, with no wasted words.

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?

Given the tool's complexity (20 params) and the presence of a full output schema, the description covers the essential context: what it does, when to use it, and what it returns. It does not enumerate every parameter, but the schema fills that gap, and the description provides enough for selection and invocation.

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?

Schema coverage is 100%, so the baseline is 3. The description adds significant value by detailing itrace option values ('i0ns', 'b', 'c', 'e') with their meanings, and by summarizing the roles of build_ids, jit, and sched_stat parameters more succinctly than the schema.

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?

The description clearly identifies the tool as a transformer of perf.data files with a specific verb ('Transform') and resource ('perf.data file'), listing concrete operations like injecting build IDs and decoding hardware traces. It also distinguishes itself from sibling tools by positioning it as a preprocessing step before perf_report or perf_script.

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?

It explicitly states when to use the tool: 'Use this as a preprocessing step before perf_report or perf_script.' This provides clear context and implies that other perf tools are for downstream analysis, not for this injection/transformation step.

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