Widget rebuild hotspots

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description nonetheless adds real context beyond them: a debug build with widget creation tracking is required, and the tool reports why it is empty otherwise — a genuine prerequisite and failure-mode disclosure.

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 tight sentences, front-loaded with the core purpose, then usage, then the prerequisite. Every sentence carries information; nothing is padded.

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 single-parameter diagnostic tool with no output schema, the description explains what is returned (widget names, file/line, ranked), the scenario it answers, and the empty-result condition. Nothing an agent needs to call it correctly appears to be missing.

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?

With a single parameter at 100% schema description coverage, the schema already documents 'limit' and its bounds. The description adds no meaning about the parameter, so the baseline of 3 applies.

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?

States a specific verb and resource ('which widgets are rebuilding and how often') and pins down the output resolution (widget name, file, line) plus the ranking rule (own code above package code). This is clearly distinguishable from siblings like get_widget_tree or diagnose_performance, which cover different concerns.

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?

Gives concrete usage scenarios ('why is this screen slow to build', finding needless rebuilds), which tells the agent when to reach for it. It does not, however, name alternative tools (e.g. diagnose_performance, get_timeline) or state when this is the wrong choice, so routing is not fully closed.

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