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

With no annotations, the description carries the full burden, and it does disclose two useful facts: a key credential is required and the call is free. However, it says nothing about pagination, result ordering, behavior when counterparty yields no matches, or whether it is a pure 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?

Three sentences plus a terse metadata line, mostly front-loaded, but the redundant first-person opener ('I want to see...') adds no information beyond the following declarative sentence and could be cut without loss.

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?

With no annotations and no output schema, the description does a fair job of explaining what the return contains (own entries, cross-agent fingerprint matches, entries naming the caller). But it leaves both input parameters unexplained, which an agent needs in order to filter correctly.

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% for two parameters, so the description must compensate and it does not. 'limit' is never mentioned, and 'counterparty' is never defined, even though the prose about 'other agents linked to me' hints at the concept without mapping it to the 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 names a specific resource (the caller's own register entries/fingerprints) and the verb (Lists), and it describes three distinct result categories. It is distinguishable from siblings like read_register or check_record by being self-scoped, though the awkward first-person opener ('I want to see...') reads like a template artifact rather than a definition.

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?

No when-to-use or when-not-to-use guidance is given, and no alternative is named despite close siblings (read_register, read_agent_record, check_record, export_register). The 'Credential: key. Cost: Free. Source: PD8.' string is operational metadata, not usage guidance.

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