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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the agent knows this is a non-destructive, closed-world mutation. The description adds that the link is time-limited, which is useful context, but it does not disclose that the result is a credential granting account access, nor any sensitivity, revocation, or rate-limit behavior. Given annotation coverage of the safety profile, a 3 is appropriate.

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?

One compact sentence, front-loaded with the core action. The 'Generate Login Link -' prefix restates the title and is mildly redundant, which keeps it from a 5.

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-value explanation is not required, and the schema itself covers all three parameters. But for a security-sensitive link generator, the description leaves out sibling differentiation and the fact that the output is a login credential with limited lifetime. Adequate but with clear gaps.

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%: redirect_url, workspace_id and expiry_minutes are all documented in the schema, including defaults and the 1–30 minute range. The description adds no parameter meaning beyond that, so baseline 3 is correct when the schema does the heavy lifting.

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: 'Create a time-limited magic login link for the authenticated user.' That is unambiguous about what the tool produces. It does not distinguish itself from similar-sounding siblings such as get_add_card_login_link or get_sender_connect_link, so it stops short of 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?

The description gives no guidance on when to use this tool versus alternatives, and no prerequisites or exclusions. 'For the authenticated user' implies the caller context but doesn't tell the agent when this is the right choice over sibling link-generators.

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