pix_list_timing_counters

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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds valuable context beyond that: counters were reported live during timing capture, they are grouped by PIX, and each row names the reporting process. No contradiction exists.

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?

Three sentences, each carrying meaningful differentiation or provenance information. The most important distinction appears early, and there is no filler.

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?

The description gives strong context about what the data is, how it differs from replay-time counters, and how it is structured. However, the absence of any parameter guidance combined with 0% schema coverage leaves some invocation details to inference, though capture_id is self-evident and the output schema exists.

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 has 0% description coverage, and the description provides no guidance for capture_id, limit, cursor_position, or timeout_seconds. It explains the conceptual counters but does not compensate for the total lack of parameter-level semantics.

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 resource as the counters carried by a timing capture and immediately contrasts it with pix_list_counters. There is no explicit verb like "list" or "return," but the tool name plus the contrast make the purpose unambiguous.

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 names pix_list_counters as the similar alternative and explains the live-vs-replay distinction that determines which one to use. It also adds a context cue about per-process rows for machine-wide captures, helping the agent select appropriately.

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