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

Annotations only say readOnlyHint=false and destructiveHint=false; the description adds meaningful extras beyond that — the pk_test_* key requirement, that it auto-completes without real OTP delivery, and an explicit authentication prerequisite with the note that start_login does NOT grant access. It stops short of saying what state change results on the verification object, but the added auth and mode constraints are substantial.

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?

Purpose and scope are front-loaded in the first sentence, and the ACCESS block is separated as its own labeled paragraph so it can be scanned independently. The auth instructions are slightly verbose but each line carries an actionable requirement.

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 single-parameter test-only tool with no output schema, the description covers purpose, key-type restriction, and the authentication prerequisite an agent needs before calling. Nothing critical is missing, though a note on the resulting verification state would fully close the loop.

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?

There is one parameter (id) with 100% schema description coverage, so the schema already documents it. The description adds no syntax, format, or source hints for the id beyond what the schema provides, so the 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?

States a specific verb and resource ('Auto-complete a verification') and scopes it precisely with the test-mode and pk_test_* key constraint. That test-mode qualifier is what separates it from the many real verification siblings (trigger_verification, submit_verification_code), though no sibling is named explicitly.

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 clear context for when to reach for it: testing flows without real OTP delivery, and it explains the access prerequisite for opening the tool at all. It does not name alternatives or an explicit 'do not use in production' exclusion, but the test-mode scope makes that largely inferable.

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