mail_awaiting_reply

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

Goes well beyond the readOnlyHint annotation: threading via In-Reply-To/References, group sends cleared on any reply, a hard 25-result cap surfaced as `truncated`, and the operational prerequisites (Full Disk Access fast path vs. SLOW AppleScript fallback). This is exactly the context an agent needs before committing.

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?

Front-loaded with the core definition, then scope, then operational caveats — every sentence adds information. It is dense with parentheticals and backticked identifiers, which costs a little readability.

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?

Covers filter semantics, ordering, scope, result cap, output-flag meaning, downstream tool compatibility, and access requirements. Even without relying on the output schema, an agent knows what it will get and what it costs.

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 0%, so the description must carry the load — it supplies the meaning of `days` (sent more than N days ago) plus the 1–365 range and default, none of which the schema encodes. Only a small gap remains (no note on invalid values).

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 resource (messages you sent) with a precise filter (no reply, older than `days`, oldest-first) and even the reason label `awaiting-reply`. An agent can distinguish it from mail_needs_response and mail_search 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?

It clarifies the account-spanning scope versus mail_needs_response and says pointers are ready for mail_body/reply_all, which orients the agent in a workflow. It never states an explicit 'use this instead of X when...' exclusion, so it stops short of full routing guidance.

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