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

Annotations already declare readOnlyHint=true, so the read-only safety is covered. The description adds valuable behavioral context: the return includes a full structured analysis, the fields='grin' option skips the heavy body text, and slash-containing ids must be passed verbatim. These details go beyond the schema and help the agent predict what happens.

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 sentences, each carrying distinct information: purpose and return payload, projection usage, and id format. The core purpose is front-loaded, and there is no wasted wording.

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 read-only get-by-id tool with two params and no output schema, the description covers purpose, return structure, parameter usage, and the critical id formatting rule. No information needed for correct invocation is missing.

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 description coverage is 100%, so both parameters are already documented. The description adds an example id and clarifies the 'grin' projection's effect ('without the heavy body text'), but this is marginal value over the schema's own descriptions.

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 states a specific verb and resource ('Fetch one BedrockNews story by id') and details the return payload (transformed article plus GRIN scores, extraction graph, key stats, trajectory, what-to-watch). This clearly distinguishes it from siblings like get_extraction_graph or get_related, which would return only a subset or related stories.

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 gives explicit guidance on when to use the fields='grin' projection to avoid heavy body text and warns that story ids contain slashes and must be passed verbatim. While it doesn't explicitly name alternative tools or say when not to use them, the context is clear and actionable for correct invocation.

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