Describe an annotation

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds valuable context beyond that by disclosing the fields returned (text, note, book with an Open in Books link, chapter, color, creation date), which matters since there is no output schema. It does not discuss auth or rate limits, but those are minor for a simple read.

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?

The content is front-loaded in the first sentence with the alternative routing in the second, which is efficient. The trailing 'Args:' block restating the single obvious parameter is mild redundancy but conventional and not harmful.

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 describe tool with no output schema, the description is nearly complete: it names the fields returned and routes to the correct sibling. It stops short of noting any error behavior for an unknown ID, but the core need to call it correctly is met.

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 0%, so the description must carry the parameter burden, and it does identify annotation_id as 'the annotation's numeric ID'. That clarifies type and target, but adds little beyond the obvious given the tool name. Adequate but thin for the single parameter.

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 (describe), resource (a specific annotation), and enumerates what detail is returned: text, note, book link, chapter, color, creation date. It also distinguishes itself from get_annotation_context, so an agent can tell the two apart without opening either schema.

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 names an explicit alternative (get_annotation_context) and the condition that selects it ('for the passage around the highlight'). This is exactly the when-to-use-the-other routing an agent needs to choose correctly between the two sibling tools.

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