read_resource

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

With no annotations, the description carries the full burden and does well: it discloses read-only semantics ('Never a write path'), the error behavior for out-of-scope URIs, and the loop-boundary ownership model. Return/pagination details are left to the output schema, which exists.

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?

Front-loaded with the core action and scope, then layered with rationale. Slightly redundant phrasing ('read-only' and 'Never a write path' restate the same idea) and some jargon ('crossing the loop boundary'), but generally tight.

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 single-parameter read tool with an output schema and full schema coverage, the description supplies the safety and error context an agent needs. It is complete enough to call correctly, missing only explicit sibling routing.

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% and the schema already enumerates the accepted schemes, so the baseline is 3. The description adds meaning about how an out-of-scope URI behaves ('resolves to nothing and errors'), which is a modest value-add over the schema.

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 one of this server's resources by URI') and immediately scopes it as read-only. It distinguishes itself from the domain siblings (list_trials, get_blob, etc.) as a generic URI-addressed reader, though it never names an alternative tool directly.

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 description implies the intended audience ('gives tool-only clients the same read surface'), which suggests when to reach for it, but there is no explicit when-to-use vs when-not guidance and no named alternative among the many siblings.

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