get_message_context

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

Annotations provide readOnlyHint, destructiveHint, idempotentHint. Description adds '(reads local cache; works while disconnected)' and 'Read-only; no side effects,' providing extra behavioral context beyond annotations. No contradictions.

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?

Three concise sentences: purpose and context, side-effect nature, sibling distinction, and return format. No wasted words, front-loaded with key information.

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?

Despite no output schema, description explains return structure. Covers offline capability and defaults. Missing error handling or missing message case, but overall sufficient for the tool's complexity.

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% with default and descriptions. Description adds value by explaining return structure: 'Returns a JSON object with the target message and arrays of messages before and after it.' Also reiterates default behavior for 'before' and 'after' parameters.

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?

Description clearly states 'Fetch a specific cached message and the surrounding messages in its chat.' Verb 'fetch' and resource identification are specific. Distinguishes from sibling 'list_messages' by noting 'for searching across many chats.'

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 states 'Read-only; no side effects' and recommends 'Use list_messages for searching across many chats.' Also mentions 'works while disconnected' as context. Does not explicitly say when not to use, but provides a clear usage context.

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