analyze_perf

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

With readOnlyHint=true annotated, the description adds value by detailing behavior: the in-memory ring versus persistent SQLite sink, the prerequisite JDATAMUNCH_PERF_TELEMETRY=1 for persistent modes, and which tools are cached. It does not contradict the annotation and provides useful context beyond the safety flag.

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 three concise sentences that front-load the core purpose and outputs. Each sentence adds distinct information: definition, return metrics, and window behavior details. No wasted words, and the structure leads with the most important information.

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?

With no output schema, the description lists the return values but does not specify the exact JSON structure. It covers the key aspects: operation, parameter effects, and environmental prerequisites. The sibling mention adds a minor contextual clue, though it could be confusing. Overall, it is sufficiently complete for an agent to invoke the tool correctly.

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?

The schema already provides descriptions for all three parameters (top, tool, window), so baseline is 3. The description adds semantics by explaining the window parameter's behavior (session vs persistent modes) and naming the cached tools, which is not in the schema. This incremental value justifies a 4.

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 states the tool's function: 'Per-tool latency and cache-hit telemetry.' It lists specific outputs (p50/p95/max latency, error rate, slowest tools, cache hit rates), making it distinct from sibling tools which focus on data operations. The verb 'returns' is explicit and resource-specific.

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?

The description provides clear context on when to use the tool by explaining the window parameter modes and the environment variable requirement for persistent data. However, it does not explicitly state when not to use it or mention alternative tools for similar tasks, missing a direct exclusion clause.

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