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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds valuable context: default output format (compact human-readable), option for JSON, behavior of expand_urls (response growth warning), and details on what each ref type returns (thread context, recent tweets). 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?

The description is concise (3 sentences) and front-loaded: first sentence states purpose and key capability, second details ref types, third explains output format and numeric id handling. No wasted words.

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 7 parameters with good schema descriptions and no output schema, the description covers the main return characteristics (tweet with thread, user with tweets, default vs JSON format). It lacks explicit details on the structure of the compact view, which would be helpful, but is still fairly complete for a get tool.

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 baseline is 3. The description adds usage context (e.g., 'prefer full URLs' for ref) and behavioral warnings (expand_urls impact), but the parameter schemas already describe each field well. The additional value is moderate.

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 fetches a tweet or user from a reference, distinguishing between tweet URLs (including handle-less /i/status/<id>) and profile URLs. It differentiates from sibling tools like glim_twitter_search by focusing on retrieval of specific items.

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?

It provides guidance on when to use the tool (fetch a tweet or user) and offers practical advice (prefer full URLs, numeric ids as quoted strings). It hints at alternatives through the expand_urls parameter description (suggesting glim_web_fetch for targeted crawls), but does not explicitly exclude other tools like glim_twitter_search.

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