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

Annotations already declare the safety profile (readOnly, idempotent, openWorld, non-destructive), so the description only needs to add context. It does: it discloses that HTML and PDF inputs are supported, that output is normalized to Markdown with metadata, and that the call costs 1 credit. Error handling, rate limits, and paywall/auth behavior remain undisclosed.

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 short sentences with the operation and output format front-loaded, followed by the cost. No filler; every clause carries information an agent can act on.

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 does the work of explaining the return value (clean Markdown plus metadata), and annotations cover the safety profile. For a two-parameter read tool this is largely complete, though it omits failure modes and any note on how it relates to crawl/extract.

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 50%: 'country' is documented in the schema while 'url' is only typed as a URI. The description adds a meaningful constraint on url (must be public, HTML or PDF) but says nothing about the country parameter or its geo-routing purpose. Baseline 3 is appropriate given the mixed coverage.

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 (Fetch) plus the resource (a public URL, HTML or PDF) and the transformation applied (main content returned as clean Markdown with metadata). It is clearly not a search, crawl, or extract tool. It does not, however, explicitly contrast itself with close siblings such as crawl or extract, so it stops short of full sibling differentiation.

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 phrase 'Fetch a public URL' implies the use case (retrieve and read one known page) and the restriction to public, presumably unauthenticated pages. There is no explicit when-to-use vs when-to-use crawl/extract, and no stated exclusions (login walls, paywalls, robots restrictions).

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