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

Goes well beyond annotations (readOnlyHint=false, openWorldHint=true) by disclosing the 24h per-person throttle, that the sendEmail counts toward it, and the exact skipped[] reasons (no email, reminded in last 24h, sending failed, plan limit). This is substantive behavioral context for a side-effecting email tool.

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?

Dense but front-loaded: the core action leads, then usage, then return shape. The single-sentence throttle clause is long but every clause carries information; minimal waste.

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?

No output schema exists, yet the description defines the return shape (sent[]/skipped[] with enumerated reasons), and covers eligibility, rate limiting, and integration with updateRequest. Nothing needed to call it correctly is 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?

Schema coverage is 50%, so description must add meaning. It clarifies recipient eligibility ('pending named recipients that have an email') and reinforces the recipientIds default (every pending one), compensating for the undocumented requestId and enriching the partially-documented parameter.

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 precise verb and resource: 'Emails the link to pending named recipients that have an email.' The scope (pending, has email) distinguishes it from generic request actions and clearly separates it from siblings like previewRequest or updateRequest.

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 names two triggering scenarios ('chase people who have not answered' or 'email recipients added with updateRequest') and points to the sibling updateRequest. It lacks an explicit when-not clause, but the eligibility constraints (pending, has email, 24h throttle) effectively bound usage.

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