read_messages

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

The description partially discloses behavior through parameter listings (e.g., mark_as_read indicates mutation). However, it does not explicitly state side effects, authorization needs, or rate limits, and lacks clarity on read-only nature when mark_as_read is false.

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 concise with a one-line summary and a bulleted argument list. It avoids unnecessary words and is well-structured, though slightly more context on usage could be added without bloat.

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?

While the return shape is specified, the description misses important behavioral details, such as the actual role of caller_agent_id (claimed required but schema says optional). With no annotations, more context is needed for a tool with 5 parameters.

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?

With 0% schema coverage, the description adds meaning by listing and briefly explaining each parameter's purpose in Japanese. This compensates for the schema deficiency, though it lacks constraints or formats.

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 agent messages, providing a verb and resource. However, it does not distinguish it from sibling tools like send_message or get_unread_count, missing differentiation.

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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of context, prerequisites, or exclusions, leaving the agent to infer usage.

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