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

With no annotations supplied, the description carries the burden and does real work: it discloses that the action applies immediately upon signature, that it is a mutation with replace semantics, that only the current funding wallet can authorize it, and that a maximum of one backup exists. It does not say what happens to a previously registered backup's authorizations or what an error looks like, leaving a small gap.

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 short sentences with the action and replace semantics front-loaded, followed by the signing requirement and the one-backup cap. The passkey analogy is arguably decorative, but it is compact and aids comprehension, so nothing is seriously wasted.

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 three-parameter governance mutation with no annotations and no output schema, the description supplies the workflow step, the signing requirement, and the cardinality limit. The remaining omissions are error behavior and the fate of an existing backup's rights, which are minor relative to what is covered.

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 the schema already documents all three parameters; the description only reinforces that challengeId comes from the challenge step and that walletSignature must come from the CURRENT funding wallet, not the backup. That is a useful emphasis but adds little beyond the schema text, so the baseline of 3 applies.

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?

States a specific verb and resource ('Register (or replace) a single backup governance wallet') and immediately clarifies the domain concept via the passkey analogy plus the effect ('Either the funding wallet or this backup can authorize future governance'). An agent can distinguish this from remove_backup_governance_wallet and from funding-wallet setup without opening the schema.

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?

Gives the operative precondition — a GOVERN action signed with the CURRENT funding wallet using challengeId + walletSignature — and a hard constraint ('Max one backup'), which together tell the agent when this call is valid and that re-calling replaces rather than adds. It stops short of naming explicit alternatives or failure paths, so it is strong context rather than a full when/when-not routing rule.

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