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

Annotations already mark the tool as read-only and open-world; the description adds useful behavioral context by stating that it returns user profiles with metadata and paginates via cursor at roughly 100 per page. It does not cover every edge case, but it meaningfully supplements the structured annotations.

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 short sentences, all informative: core purpose, key exclusion/alternative, output shape, and pagination. No redundant phrasing; the most important behavioral distinction is front-loaded.

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 simple two-parameter read-only tool with full schema coverage, the description is nearly complete: it names the resource, output, pagination, and main alternative. The lack of an output schema is partially offset by 'Returns user profiles with metadata', though exact response fields are not specified.

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 fully documents tweetId and cursor. The description echoes the cursor pagination behavior but does not add significant new semantic detail beyond what is already present in the schema.

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 uses a specific verb and resource ('Fetch users who retweeted a specific tweet') and explicitly distinguishes itself from the quote-tweet tool by name. An agent can immediately see what this tool does and how it differs from get_tweet_quotes.

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 clearly states the scope (simple retweet action), explicitly excludes quote-tweets, and names the alternative tool to use for that case. This gives the agent direct routing guidance with no ambiguity.

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