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

Goes well beyond annotations: it discloses the supersede/invalidation side effect, rate limiting with a wait-time hint and 'don't spam' guidance, dev-environment return of the raw code, and the 'already verified' failure mode keyed to status past `draft`. This is behavior an agent could not infer from readOnlyHint=false and idempotentHint=false alone.

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-loaded one-line purpose, then headed blocks (When / Before you call / Returns / On error) that let an agent scan to the relevant part. No filler sentences; every line carries operational meaning.

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?

Covers the full lifecycle for a simple one-param mutation: trigger conditions, prerequisites, side effects, success confirmation, and both documented error branches. Output schema exists, so return-value detail is appropriately brief.

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?

Only one parameter and schema coverage is 100%, with the schema itself linking applicationId back to create_application. The description adds no syntax, format, or sourcing detail beyond what the schema already states, so baseline 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?

Specific verb+resource: 'Issue a fresh 6-digit verification code,' plus the key differentiator 'supersedes any prior unconsumed code,' which separates it from verify_email and create_application in the sibling set. An agent can pick this tool 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?

The 'When' block enumerates the three triggering conditions (no code received, code expired, locked out by wrong attempts) and 'Before you call: nothing' pre-empts prerequisite hunting. Error paths explicitly route to get_status when the application is already verified.

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