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

Annotations already declare destructiveHint=true, readOnlyHint=false and openWorldHint=true; the description adds genuinely non-structured context — the elided trust guarantee ('proves the same key signs each time, not who holds it') and the fact that the call is free. It omits what happens if an identity is already registered (idempotentHint=false raises the question) and says nothing about the read mode's output, but it adds real value 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?

Three tight sentences: purpose first, then per-mode instructions, then the caveat and cost. Every sentence carries information; nothing is redundant 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 dual-mode, destructive, nested-object tool with no output schema, the description covers the write path reasonably but says nothing about return values for either mode, duplicate registration behavior, or failure conditions. Adequate but with visible gaps an agent would hit in practice.

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 coverage is 100%, so both parameters are already documented, giving a baseline of 3. The description does add the llpro1: id format and clarifies that the nested identity object must be self-signed and where its spec lives, but does not explain required fields inside that nested document.

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 two concrete operations (register, read) on a specific resource (agent identity) and even names the id format (llpro1:...). It is clear without opening the schema, though it never distinguishes itself from near-siblings like agent_identity_check or agentrecord_lookup, leaving overlap ambiguity.

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 clearly branches usage by argument: send a self-signed identity document to register, send {id} to read. There is no guidance on when to prefer this over the adjacent identity/lookup tools, and no prerequisites or exclusions are given.

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