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

Annotations only supply readOnlyHint, so the description carries the rest and does it well: it flags the 'public' access constraint and warns that the result is a JSON string that must be parsed. It also routes long pages to smart_context_gate. It omits failure modes (timeouts, non-HTML content, truncation) and any rate-limit or auth expectations, which keeps it short of a 5.

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?

Labeled front-loaded lines (Purpose / When to use / When NOT to use / Returns / Composes with) with no filler. Each line conveys a distinct decision-relevant fact, so a scanning agent gets the routing signal in the first sentence.

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 full schema coverage, an output schema, and a readOnly annotation, this covers purpose, routing, return shape, and composition. Missing only edge-case behavior such as what happens on fetch failure or non-text content, which is a minor gap given the output schema exists.

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 100%, with both url and timeout documented in the schema, so the baseline is 3. The description adds only the 'public HTTP(S)' restriction and says nothing about timeout semantics, so it does not meaningfully exceed what the schema already 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?

Names a specific verb and resource: fetch a public HTTP(S) URL and return Markdown-friendly content. The scope word 'public' and the 'Markdown-friendly content' phrasing distinguish it cleanly from smart_search (which finds URLs) and from reading content already in context.

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?

Explicitly gives the trigger ('user provides a link and needs the page body or article text'), the exclusions ('full text is already in the conversation, or the target is not a fetchable URL'), and the alternative ('smart_search when no URL yet'). Nothing is left to inference.

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