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

The annotations already show readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context about what the returned entries contain (evidence tier, reliability, access date) and that omitting the parameter returns the full registry, which goes beyond the 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?

The description is two sentences, front-loads the core behavior and return contents, and includes the usage guidance and sibling differentiation without any filler. Every sentence earns its place.

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?

Given a single optional parameter, rich annotations, and an output schema, the description fully equips an agent to invoke the tool correctly. It clarifies the default behavior, what data to expect, and when to choose the tool over a sibling, so nothing essential 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?

The input schema already documents object_id completely, including its optionality and semantics, and schema description coverage is 100%. The description restates the omit-to-get-whole-registry behavior but does not add meaning beyond what the schema already provides, so the baseline 3 is appropriate.

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 exactly what the tool returns: the source registry, optionally restricted to sources cited by one object, with evidence tier, reliability, and access date. It clearly distinguishes itself from get_entity by noting that get_entity already reports which sources a claim cites, so an agent can tell the tools apart.

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 explicitly says when to use this tool: when you need the registry entry behind a citation, or when you want the whole registry to judge the corpus before trusting it. It also names the relevant sibling alternative, get_entity, and explains how that other tool differs, giving clear routing guidance.

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