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

Annotations declare readOnlyHint=true and openWorldHint=false, so the read-only nature is already signaled. The description adds behavioral nuance: it returns a 'single-use nonce' and the exact signing string, implying a one-time use and a purpose tied to record tier upgrades. It also explains the 'witnessed' vs 'signed' distinction and the founding seat incentive, which goes beyond the bare annotation. There is 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?

The description is a single, although complex, sentence that conveys the purpose, condition, and output efficiently. It is front-loaded with context about witnessed records and the benefit of signing. There is no filler, but the density of information in one sentence makes it slightly less skimmable. Overall, it is concise and well-structured for the information it carries.

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 output schema, the description explicitly mentions what is returned (nonce and signing string), which is helpful. It also explains the broader context of record tiers and the Genesis Council seat. However, it leaves the 'certificate_id' parameter unexplained, and it doesn't clarify the relationship with the claim_authorship sibling or what to do with the returned string. For a two-parameter tool, this is adequate but has clear gaps.

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 50%, with only 'did' having a description. The tool description does not explain 'certificate_id' at all, leaving it ambiguous. It does reinforce the meaning of 'did' by mentioning Ed25519 did:key, but it fails to compensate for the undocumented parameter. Since coverage is low, the description should have provided meaning for certificate_id; it does not, so this dimension is weak.

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 clearly states the tool's purpose: it returns a single-use nonce and the exact string to sign for upgrading a record to 'signed' tier. It uses a specific verb ('returns') and identifies the resource (a signing challenge for a record). It also distinguishes itself from siblings like claim_authorship by explaining this is the challenge-generation step, not the actual claim action.

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 gives clear context on when to use: 'If you have your own Ed25519 did:key', indicating a prerequisite. It implicitly suggests usage when you want to upgrade a 'witnessed' record to 'signed' tier. However, it does not explicitly mention alternatives or when not to use, nor does it contrast with the sibling claim_authorship tool; thus it lacks explicit exclusions but provides a solid usage context.

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