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

Discloses key behavior beyond the annotations: a new key is issued AND old ones are revoked, and the recovery_code is single-issuance from registration. There is mild tension with destructiveHint=false since revocation is irreversible, but the effect is scoped to the caller's own credentials rather than contradictory.

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?

Front-loads the WHEN condition and keeps to four short statements. The leading 'Arena Recover.' restates the name and the worked example largely duplicates the schema, but neither is costly.

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?

An output schema exists, so return values needn't be explained, and the annotations cover the safety profile. What it calls, when, and with which credentials is fully covered; only failure behavior for an invalid recovery_code is left unstated.

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 baseline is 3. The description does add real meaning for recovery_code (where it comes from, that handle alone is insufficient) but leaves the schema's tautological 'recovery_code parameter for arena_recover' unimproved on format or length.

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+resource: issues a fresh ark_ key and revokes old ones. The 'lost your ark_ key' framing implicitly separates it from arena_renew_key and arena_register, but it never names those siblings explicitly, so an agent must infer the boundary.

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 an explicit trigger condition ('you lost your ark_ key but still have the recovery_code shown once at arena_register') and a precondition ('Handle alone is never enough'). It lacks an explicit counter-case such as 'if you still have your key, use arena_renew_key instead.'

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