verify_magic_link

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

No annotations are provided, so the description carries full burden. It discloses key behaviors: creates user if nonexistent, token is single-use, expires in 15 minutes. It also indicates return values (access_token, refresh_token). This covers side effects and constraints well, though it could mention rate limits or authorization requirements.

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 sentences, each serving a purpose: main action, side effect, constraints. No wasted words. Information is front-loaded.

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?

Given no output schema, the description specifies return values (access_token, refresh_token). It covers behavior, side effects, and constraints. For a tool of this complexity, the description is fully informative.

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 baseline is 3. The description does not add new meaning beyond the schema's parameter descriptions. It merely restates 'code' and 'token' in the context of exchange, which is already clear from the schema.

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?

The description uses specific verbs and resources: 'Exchange a magic link token for access_token + refresh_token'. It also adds unique behaviors (user creation, single-use, expiry) that distinguish it from nearby tools like 'request_magic_link' which likely sends the link, and other auth tools.

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 description implies when to use (when you have a magic link token) but does not explicitly state alternatives or when not to use. For example, it doesn't mention that this is for verifying the link after the user clicks it, nor does it contrast with other authentication methods like password or passkey.

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