mail_waiting_on_mePeople the user has written to before whose latest email came after the user's latest email to them, in the last two weeks, longest wait first: name, email, mailbox, when they last wrote, when the user last wrote, and the days waited.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | Max people (default 25, max 100). |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
readOnlyHint=true already establishes this as a safe read, and the description goes further by disclosing the two-week time bound, the sort order, the underlying inequality logic, and the exact output columns. It does not mention total counts or pagination behavior, so it stops short of full behavioral coverage.
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?
A single dense sentence that front-loads the definition before the output columns; every clause is load-bearing. It is long-ish and slightly run-on, but there is no filler.
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?
With no output schema, the description compensates by enumerating the returned fields, and the read-only annotation covers the safety profile. The only omissions are pagination/total-count behavior and any routing hint toward the sibling slack tool.
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?
Only one parameter (limit) exists and the schema already documents it fully ('Max people (default 25, max 100)'), giving 100% coverage. The description adds nothing about the limit, so baseline 3 is appropriate since the schema carries the entire burden.
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 precise, self-contained definition of the target set (people written to whose latest email postdates the user's latest email, within a two-week window), plus the ordering and returned fields. This lets an agent distinguish it from siblings like slack_waiting_on_me, quiet_contacts, or top_message_correspondents without opening any schema.
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?
The two-week window and 'longest wait first' ordering imply a follow-up / unreturned-mail use case, but there is no explicit when-to-use or when-not-to-use statement, and the sibling slack_waiting_on_me is never named as the analogous alternative. Usage is inferable but not directed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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