log_message

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

Discloses that the tool records the current local datetime and timezone offset. No annotations exist, so description carries the burden. Could mention return value, but core behavior is transparent.

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?

Two concise sentences: first states purpose, second gives usage guidance. No unnecessary words, well-structured.

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?

Lacks information about the return value (e.g., does it return a message ID or just success?). Also does not explicitly mention prerequisite of a valid session (though schema covers session_id). For a simple logging tool, mostly adequate but missing response details.

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 covers session_id and content descriptions (67% coverage). Description adds value by explaining how to use the role parameter in context of when to call.

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 'Record a single message (user or assistant)' with a specific verb and resource. It distinguishes from the sibling tool 'log_exchange' by focusing on individual messages.

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?

Explicit instructions: 'Call before responding for user messages, and before sending for assistant messages.' This provides clear context on when to invoke the tool.

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