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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds the useful point that this only formats already-prepared data rather than fetching it, but says nothing about output or validation behavior.

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?

Two short sentences, front-loaded with the verb and resource, with zero filler. Its brevity is a problem for coverage, but that is penalized elsewhere, not here.

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?

A 7-parameter tool with no schema descriptions and no output schema needs the description to explain the remaining fields; it covers roughly two of seven. An agent cannot infer what 'eyebrow', 'warnings', or 'breakdown_title' should contain.

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 7 parameters, so the description must carry the load, yet it only glosses 'metrics' and 'breakdown rows'. title, eyebrow, subtitle, warnings, and breakdown_title are entirely undocumented 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 states a specific verb and resource ('Renders a TrackingTime time summary card') and clarifies the input is 'prepared metrics and optional breakdown rows'. It is distinguishable from most siblings (render_timesheet, render_project_summary) by naming a time summary card, though it does not call out those siblings explicitly.

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?

'Use after fetching or computing summary data' gives a sequencing hint but no conditions for choosing this over other render_* tools, and no exclusions. The usage is implied rather than prescribed.

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