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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so safety is covered. The description adds the workflow context (consumes prepared records) but doesn't state what the tool actually returns — presumably a UI/presentation payload — nor whether it has side effects, so it only modestly exceeds what annotations provide.

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, purpose first then usage guidance, with zero filler. Every clause carries 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?

For a tool with 7 parameters, nested array-of-object inputs at 0% schema description coverage, and no output schema, the description does far too little. It should clarify what 'prepared' means and what the render produces, which is exactly the information an agent would need.

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% and there are 7 params including arrays of invoice objects and metrics objects. The description only vaguely gestures at 'prepared invoice records and billing metrics' and never explains the invoice object fields, metrics shape, warnings, or invoices_title, leaving the schema to speak entirely for itself.

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+resource: renders a TrackingTime invoice list from prepared records and metrics. This distinguishes it from mutating siblings like create_invoice or list_invoices, though it doesn't explicitly contrast with the other render_* tools (render_entity_list, render_report_list).

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?

Explicitly says when to use it: 'Use after listing invoices or fetching invoice details,' which establishes a clear workflow ordering. It doesn't name an alternative or state when not to use it, so it falls short of a 5.

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