verify_2fa_magic_link

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

With no annotations, the description carries the burden of behavioral disclosure. It explains that no code is needed and that the token itself is the proof, and it warns about access requirements. However, it does not disclose side effects (e.g., whether the token is consumed, whether a session is created), nor does it mention prior steps like an active 2FA challenge from start_2fa.

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?

The description is compact: two sentences plus a clearly marked ACCESS section. The core behavior is front-loaded, the differentiator is stated immediately, and access prerequisites are separated. Every sentence earns its place with no filler or repetition of the schema.

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 tool with no output schema, the description is largely complete: it states the action, the token input, the access condition, and how it differs from code-based 2FA. The main gap is that it does not explicitly state whether an active 2FA challenge (e.g., from start_2fa) is required before calling this tool, though 'Complete a 2FA challenge' implies one exists.

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 coverage is 100% – the only parameter 'token' is fully described in the schema as 'Magic link token from the verification email'. The description adds only minor reinforcement ('received via email', 'token itself is the proof') without introducing new semantic detail like token format, expiration, or single-use behavior. Baseline 3 applies given the high schema coverage.

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 a specific verb ('Complete') and resource ('2FA challenge') and immediately clarifies the mechanism: 'using a magic link token (received via email)'. It also distinguishes itself from the likely alternative by stating 'No code submission needed — the token itself is the proof', which differentiates it from verify_2fa without needing to inspect 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 description provides clear context for when to use this tool: when you have a magic link token rather than a code. The ACCESS section explicitly states prerequisites (Proof account, API key or prior start_login session). However, it does not explicitly name sibling alternatives or say 'use verify_2fa for OTP codes', leaving some inference to the agent.

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