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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new behavior: redirects are deliberately not followed, and it enumerates the four returned fields, which the agent would otherwise have to guess given there is no output schema.

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 dense sentences with no filler. The operation and its return payload come first, and the redirect/method constraint is packed into a parenthetical rather than padded into its own paragraph.

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 two-parameter read tool with no output schema, the description compensates well by naming the exact return fields and the RFC basis for status interpretation. Minor omissions remain (timeout behavior, error responses for unreachable hosts), but nothing essential to correct invocation 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%, and the schema already documents both parameters including the method trade-off ('HEAD is faster; GET is what browsers do'). The description's mention of GET/HEAD merely echoes the schema, so the baseline 3 for full-coverage schemas applies.

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 (Request) and resource (URL) and enumerates exactly what is returned: HTTP status code, status text, response time, response headers. The parenthetical '(GET or HEAD, redirects not followed)' cleanly separates it from the sibling trace_redirects, so an agent can pick between them without opening a schema.

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 'redirects not followed' note implicitly signals when this tool is appropriate versus trace_redirects, and the RFC 9110 reference sets expectations for status interpretation. However, no sibling is named and no explicit when-to-use/when-not condition is stated, leaving the routing guidance to inference.

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