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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description builds on this with ordering, independent transcript/recording states, exclusion of bodies/signed URLs, cursor behavior on empty filtered pages, and a permission requirement. No contradiction with annotations.

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?

Four crisp sentences, each earning its place: purpose and ordering, a limit usage tip, payload scope, and auth plus pagination. No filler or repetition.

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 read-only list tool with an output schema, the description covers ordering, scope, authorization, and pagination well. However, given 9 parameters at 0% schema coverage and no enums, the undocumented filter semantics leave an agent guessing, so completeness falls short of excellent.

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%, so the description must compensate for the 9 optional parameters. It only clarifies 'limit' and 'cursor'; the remaining filters (phone, outcome, integrationId, recordingState, transcriptState, to, from) are left undefined, with no enums or defaults in the schema. This is a significant gap for an agent trying to filter correctly.

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: 'List your organization's WhatsApp call history,' and adds ordering ('newest started first'). It distinguishes itself from sibling download tools by noting it 'never bodies or signed URLs' and from generic list_calls by scoping to WhatsApp.

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 provides actionable usage context: 'Requires whatsapp_calls:read' for authorization, 'Use limit:2 for the latest two' as a common pattern, and 'Continue with the returned cursor, including on empty filtered pages' for pagination. It does not explicitly name alternative tools, but the exclusion of bodies and signed URLs implies recording retrieval should use other tools.

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