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

Annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false) cover the safety profile, and the description adds material context beyond them: a per-call cost of $0.002 USDC on Base charged per successful call via x402, plus the character ceiling and output format. It does not describe failure/retry behavior or what happens on an over-limit input, which is the remaining gap.

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 sentences, front-loaded with purpose and scope, then usage with the alternative, then the cost caveat. Every clause carries information; no filler or repetition of the title.

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?

No output schema exists, and the description compensates by stating the return shape (sentences plus bullet key points). It covers purpose, scope limit, routing to the sibling, and the payment model, which is everything an agent needs before calling.

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 both parameters (text and sentences) are already documented in the schema; the baseline is 3. The description restates the 12,000-character limit but adds nothing about the 'sentences' length control (1-8, default 3) beyond what the schema already says.

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?

Specific verb (summarize) plus resource (text) with an explicit scope limit of 12,000 characters and a stated output shape (a few sentences plus bullet key points). It also distinguishes itself from the near-identical sibling 'summarize' by naming it as the URL-based alternative.

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 when to use it ('long emails, documents, transcripts and tool outputs') and when to route elsewhere ('for a web page by URL, use /summarize'), naming the alternative directly. Nothing about tool selection is left to inference.

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