cad_timing

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is given. The description adds that one mode shells out to the icetime binary, which is meaningful context, but says nothing about execution cost, timeouts, failure behavior, or what happens with a malformed report - gaps that matter for a tool with a 180s default timeout.

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?

A single front-loaded sentence with the two capabilities stated up front and no filler. Every clause carries distinct 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?

An output schema exists, so return values need not be described, and the read-only annotation carries the safety burden. However, a tool that optionally spawns an external binary and accepts a clock frequency and timeout leaves the agent guessing about required inputs per mode, which the one-line description does not resolve.

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 description coverage is 0% across the five nested fields, so the description must compensate and only partly does: its 'parse vs run icetime' framing effectively explains the action enum. The device, clock_mhz, and timeout_s fields - the latter two directly affecting icetime execution - receive no explanation anywhere.

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 names two specific operations on specific artifacts: parsing nextpnr/icetime timing reports, and running icetime against an .asc file. This clearly separates it from siblings like cad_synthesize or cad_simulate, though it never explains what a timing report yields.

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 two modes implicitly route usage (have a report -> parse; have an .asc -> run icetime), but this is left to inference rather than stated as a condition. No prerequisites, no mention of when timing analysis is the right step versus simulation or verification, and no sibling alternatives are named.

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