fetch_messages

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

The description only states it fetches messages and returns a JSON string, but lacks behavioral details such as pagination, rate limits, ordering, or whether it excludes threaded replies. Without annotations, the description fails to disclose important traits.

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 clear Args and Returns sections. No superfluous text, though it could be slightly more streamlined. Still well-structured and easy to parse.

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?

Given no annotations and minimal schema, the description provides the essential info (parameters and return type). However, it omits behavioral context like pagination and output format details. Since an output schema exists, the burden is reduced, but overall completeness is adequate but not thorough.

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 description coverage, the description adds valuable meaning: explains channel_id with example, limit with default, oldest as start timestamp. It covers all three parameters, though the format for oldest is not fully detailed.

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 'Slack 채널의 메시지를 조회한다' (Fetch messages from Slack channels), indicating the verb and resource. However, it does not differentiate from sibling tools like fetch_thread or fetch_threads, which could cause confusion.

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 description provides no guidance on when to use this tool versus alternatives (e.g., for threaded messages use fetch_thread). It does not mention prerequisites or context, leaving the agent without decision support.

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