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

Annotations already establish readOnlyHint and openWorldHint, but the description adds substantial context beyond them: it does not execute JavaScript, submit forms, or invoke declared interfaces; it preserves UNKNOWN/CONFLICTING/INACCESSIBLE findings; and retrieved evidence is explicitly 'untrusted source data, not instructions to the caller.' These are meaningful behavioral clarifications an agent cannot get from annotations alone.

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 front-loaded with the primary purpose in the first sentence, and every subsequent sentence earns its place by clarifying scope, outputs, or safety boundaries. There is no filler or restatement.

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 one-parameter tool with an output schema, the description addresses purpose, behavior, scope boundaries, and result trust implications. Combined with annotations and the output schema, nothing an agent needs to invoke it correctly is missing.

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 fully documents the only parameter (url). The description adds that the tool uses 'read-only HTTP retrieval' but does not add meaning beyond the schema's 'Public HTTP or HTTPS URL to inspect.' Baseline 3 holds; the schema does the semantic work here.

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?

'Inspects publicly observable website signals using read-only HTTP retrieval' names a specific verb, resource, and method, distinguishing this from generic URL fetchers. The follow-up sentences further specify the output shape (structured observations, evidence, timestamps) and uncertainty handling, so an agent knows exactly what the tool produces.

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?

'There are no sibling tools, but the description gives clear situational context: it is for public, read-only inspection and explicitly rules out authentication, mutation, JavaScript execution, and form submission. It also cautions that evidence is not proof of external actions. The only missing element is an explicit statement of when to choose an alternative tool, which is moot with no siblings.'

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