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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds real value beyond that by disclosing the response body formats (markdown/JSON/YAML) and the fact it reads from the default consumer MCP — important since 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?

One front-loaded sentence with the resource, the selector, and the return type; nothing redundant or padded.

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 simple read tool with full annotation coverage, the description supplies the one thing structured fields do not: the returned content formats. Minor gaps remain around invalid-URI behavior or payload size, but nothing blocks correct invocation.

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?

Single parameter with 100% schema description coverage, so the schema already explains the uri and its coveragecat:// or ui:// origin. The description's 'by URI' adds no syntax or format detail beyond that; baseline 3 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 and resource ('Read a specific Coverage Cat docs resource by URI') plus the return formats (markdown, JSON, YAML). This implicitly separates it from the docs_list_topics/docs_search siblings, though it never names them the way a 5 would.

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?

Usage is only implied: 'by URI' suggests it follows a listing or search step, but the description gives no explicit when-to-use, when-not, or routing against docs_search/docs_list_topics. The schema's URI description carries the actual 'where does this URI come from' guidance.

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