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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral context beyond those: token-budget truncation, DOM-density boilerplate stripping, API key requirements, flat pricing per read, HTTP 402 for insufficient balance, and HTTP 422 with refund for fetch failures. No contradiction with 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?

Four sentences, each earning its place: purpose, processing behavior, auth/billing, and failure handling. The core purpose is front-loaded, and no padding or redundant restatement of the 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?

For a straightforward read-oriented tool with no output schema, the description covers what the tool does, how it processes input, what credentials are needed, what it costs, and what errors to expect. Nothing essential is missing for an agent to invoke it correctly.

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 parameters are already fully documented. The description only adds marginal context around max_tokens via 'strict token budget' and 'estimated tokens' but does not meaningfully enrich the meaning of url, include_links, or preserve_tables beyond what the schema provides.

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 opens with a specific verb and resource: 'Fetch a web page and return clean GitHub-flavored markdown.' This unambiguously distinguishes the tool from siblings like convert or generate, even without naming them. The title 'Web Page Reader' reinforces the purpose.

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 gives clear context for when to use this tool: whenever a web page needs to be fetched and converted to markdown. It does not explicitly mention when not to use it or name an alternative, but the use case is communicated clearly enough for an agent to select it appropriately.

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