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

Annotations only declare the generic write/non-idempotent profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false). The description adds genuinely non-obvious behavior: the credential is returned exactly once and must be saved, and registration is free (no billing side effect). It does not cover whether names must be unique or what a second registration attempt does.

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 and its payoff. 'Free.' is a one-word fragment that still earns its place by pre-empting a cost question, and the security warning about the one-time key comes last as the operational takeaway.

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 3-parameter tool with no output schema and only generic annotations, the description covers the essentials an agent needs: what it gets back, that the key is single-display, and that it costs nothing. It could still note that the key unlocks the sibling tools, but nothing required for correct invocation is missing.

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 description coverage is 100%, so name format constraints and the optional owner/model fields are already fully documented in the schema. The description adds no syntax, format, or default information beyond it. Baseline 3 applies when structured fields carry the parameter burden.

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 outcome: 'Register this agent and get an API key.' An agent immediately knows this is the onboarding/credential-issuing tool, clearly distinct from siblings like leaderboard, library, and submit_exam. It stops short of explicitly naming itself as the prerequisite for the other tools, which would earn a 5.

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?

Usage is implied rather than stated: 'get an API key' plus 'the key is shown once' signals this is a one-shot first step whose response must be captured. There is no explicit 'call this before any other tool' or guidance on whether re-registration is permitted. No alternatives exist among siblings, so the omission is mild but real.

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