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

With no annotations, the description carries the burden and does meaningful work: it discloses the one-time secret return ('bearerKey once'), the condition that triggers it (agentPublicKey omitted), the required scopes, and the environment feature gate. It omits what happens on failure, whether caps are enforced at mint time, and how the credential can later be revoked.

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, front-loaded with the action, then the return semantics, then the prerequisite gate. No filler, and the ordering matches how an agent needs the information.

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 5-parameter creation tool with no output schema and no annotations, the definition covers the security-critical facts an agent needs before calling: required scopes, feature gate, and the one-time secret behavior. Minor gaps remain around authorization failure modes and the interaction between access mode and the per-wallet caps.

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 already 80%, so the baseline is 3; the description earns above that by explaining the crucial behavioral consequence of the agentPublicKey parameter — that omitting it yields a bearerKey exactly once. It says nothing extra about access, expiresAt, or the grant caps, which the schema already covers.

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?

Uses a specific verb ('Mint') and a well-scoped resource ('vault-scoped credential for an existing wallet'), which makes creation clearly distinct from revoke_vault_credential and update_vault_credential. It stops short of naming a sibling explicitly, so sibling differentiation is implicit rather than stated.

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 concrete preconditions: the wallet must already exist, the caller needs treasury plus keys:manage scopes, and the FORTFI_VAULT_CREDENTIALS_ENABLED flag must be on. It does not say when to prefer this over update_vault_credential or what to do when the feature flag is off, so no explicit alternative routing.

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