read_mail

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

No annotations, so description carries full burden. It discloses read behavior (vs mutation), the two scopes and their sources, the conditional behavior (list vs read), the ordering of threads (by last touched), and the 'since' timestamp filtering. No contradictions and sufficient transparency for a read-only 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?

The description is front-loaded with a concise first sentence, then a scopes paragraph, and a closing note from the Architect. The note is slightly tangential but adds practical guidance. All sentences serve a purpose, but the note could be seen as extra length. Overall, it is well-structured and not verbose.

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 tool with no output schema, the description covers behavior, scopes, ordering, and the since parameter. It does not detail the exact fields returned in messages or thread lists, which might be useful, but the essential usage is clear. Given the sibling context and schema richness, it is fairly complete.

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 100%, so baseline is 3. The description adds value by explaining the conditional interplay (thread omitted vs provided), the default scope, and the ordering caveat, which are not fully captured in the schema. However, individual parameter descriptions are clear, so the description complements rather than compensates.

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 clearly states the tool reads messages from a thread or lists available threads, with specific verb+resource. It differentiates from siblings by focusing on read operations for mail, distinct from read_zine, post_message, etc.

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 explains when to list (thread omitted) vs read (thread provided), introduces the two scopes (local/relay) with defaults, and includes the Architect's note advising to check existing threads before speaking, which implies using this tool before posting. This provides clear context and alternatives.

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