list_messages

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

With no annotations provided, the description carries full burden for behavioral disclosure. It usefully states that returns are 'paginated message history' and lists content types included, which goes beyond basic retrieval. However, it doesn't mention permission requirements, rate limits, whether all message types are always included, or what the pagination structure looks like. For a read operation with 6 parameters, more behavioral context would be helpful.

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 appropriately concise with two sentences. The first sentence states the core purpose and return content. The second provides usage context. No wasted words, though it could be slightly more front-loaded by mentioning pagination earlier given its importance.

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 operation with 6 parameters and no annotations or output schema, the description provides adequate but incomplete context. It covers the basic purpose and usage but lacks details about the return format structure, error conditions, or how pagination works in practice. With no output schema, the agent must infer the response format from the description alone, which is insufficiently detailed.

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 description coverage is 100%, so the schema already documents all 6 parameters thoroughly. The description doesn't add any parameter-specific information beyond what's in the schema. It mentions 'paginated' which relates to 'before'/'after' parameters, but doesn't explain their semantics further. Baseline 3 is appropriate when schema does the heavy lifting.

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's purpose: 'Retrieve messages from an agent's conversation history.' It specifies the resource (messages) and action (retrieve), and mentions the content includes user messages, assistant responses, tool calls, and system messages. However, it doesn't explicitly differentiate from potential sibling tools like 'search_memory' or 'search_archival_memory' that might also retrieve message-like data.

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 implied usage guidance: 'Use for reviewing past conversations or debugging agent behavior.' This suggests appropriate contexts but doesn't explicitly state when NOT to use this tool or name alternatives among the many sibling tools. It lacks clear exclusions or comparisons to tools like 'search_memory' or 'get_agent_summary' that might serve overlapping purposes.

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