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

Annotations only cover readOnlyHint and openWorldHint; the description adds material behavioral facts the annotations do not: the paid x402 model and exact cost ($0.006 USDC per call), which an agent must know before invoking. It also enumerates the return contents, useful since there is no output schema. Missing rate limits/latency, but the added context is substantive.

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, output scope front-loaded and pricing last. The long enumeration of returned fields is dense but each item earns place since no output schema exists.

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?

With no output schema, the description steps up by listing the return contents, and it discloses the payment requirement. The main gap is the unresolved url/text parameter contract (mutual exclusivity, requiredness), which matters because both params are optional and undescribed.

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 0% for the two parameters, and the description's 'from text or a URL' is the only hint that these map to the text and url inputs. It never says whether both are accepted together, whether one is required, or what formats are valid, so it only partially compensates for the undocumented 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?

States a specific verb (extract) plus resource (SEO keywords) and enumerates the returned artifacts: primary keywords with relevance, long-tail phrases, entities, topics, search intent, title and meta description. It does not differentiate itself from nearby siblings such as seo, serp, entities, or extract, so it is clear but not sibling-distinguishing.

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 scopes the input ('from text or a URL') but gives no when-to-use guidance, no conditions for choosing this over seo/serp/entities, and no note on whether url and text are alternatives or can be combined. An agent must infer usage entirely.

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