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 non-obvious behavioral context: the return is markdown, it contains followable links for navigation, and it is the complete page rather than a snippet. It does not cover error behavior for invalid or unreachable URLs, which keeps it below 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?

Four short sentences, front-loaded with the core action and followed by the routing rule and return characteristics. The opening sentence and 'Use this when you have a page URL and want to read its content' partially overlap, but nothing is padded meaningfully.

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 carries the burden of describing returns and does so (full markdown, embedded navigation links), plus the relationship to searchDocumentation. What is missing is failure behavior for bad URLs, a minor gap for a single-parameter read tool.

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%, so the baseline is 3, but the description adds real value: it specifies that full URLs are accepted and gives a concrete example format (https://docs.blockrazor.io/getting-started), clarifying what string to supply beyond the schema's bare 'The URL of the page to fetch'.

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) and resource (full markdown content of a documentation page) with named source (BlockRazor). It is clearly separable from sibling searchDocumentation by the 'full page vs partial results' distinction.

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 states the triggering condition ('when you have a page URL and want to read its content') and names the alternative it complements: searchDocumentation returns partial content, getPage retrieves the complete page when more detail is needed. When-to-use and alternative routing are both present.

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