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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds genuine behavioral context beyond that: the return is a string and binary payloads are base64-encoded, which materially affects how an agent must handle the result. It omits error/not-found behavior, but the encoding disclosure is a real addition.

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?

Three short sentences, front-loaded with the core action and then the two caveats an agent needs. Zero wasted words, though the 'Returns...' sentence partially overlaps the existing output schema.

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 an output schema present and annotations covering the read-only profile, the description need not detail return structure. It supplies the URI-construction nuance and encoding caveat, leaving only minor gaps such as invalid-URI or missing-resource behavior.

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 a single string parameter, so baseline would be 3. The description goes beyond the schema by specifying that templated resources require the URI with template parameters already filled in, which is meaningful semantic guidance the schema does not carry.

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?

The description gives a specific verb and resource ('Read a resource by its URI'), which cleanly separates it from list_resources and the legal_* tools. It does not explicitly name or contrast with any sibling, so it lands at a solid but not exemplary 4.

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?

It explains how to construct the URI for static vs templated resources, which is practical invocation guidance, but never states when to pick this tool over alternatives (e.g., list_resources first, or the legal_* lookups) or any preconditions. Usage is implied rather than stated.

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