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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds meaningful behavioral context: the tool can return either the whole registry or a filtered set depending on object_id, and it specifies the output attributes (evidence tier, reliability, access date). No contradiction with annotations.

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?

Two sentences, front-loaded with the core behavior, then targeting the use case and sibling differentiation. Every clause earns its place; there is no redundancy or padding.

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 tool with one optional parameter, rich annotations, an output schema, and a clear differentiator from get_entity, the description is fully sufficient. It tells the agent what the tool returns, when to use it, and how it relates to a sibling tool.

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%, and the schema already explains that object_id restricts results and can be omitted for the whole registry. The tool description mainly restates this same information, adding no substantially new parameter semantics beyond what the schema already provides.

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: retrieving the source registry or the sources cited by one object, including evidence tier, reliability, and access date. It actively distinguishes itself from get_entity, which already tells which sources a claim cites, making the tool's unique scope clear.

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?

Explicitly explains when to use this tool: when you need the registry entry behind a citation, or the whole registry to judge the corpus. It also calls out get_entity as the alternative for seeing which sources a claim cites, providing clear routing guidance.

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