Login

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

Annotations already declare the operation as non-readOnly, non-idempotent, non-destructive and open-world, so safety is covered. The description adds one genuinely useful behavioral fact beyond the annotations: the call returns a session token. It says nothing about failed-login behavior, lockout/rate limits, or token lifetime.

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?

Short, front-loaded, and the core sentence (credentials in, session token out) appears early. The leading 'Login' line duplicates the title and the trailing 'Immich operation / tag' line is metadata filler, but neither is costly.

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?

With no output schema present, the description partially compensates by naming the returned session token, but it omits how the token is used downstream and any error or prerequisite context. Adequate but with clear gaps for an authentication entry point in a 200+ tool server.

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% for both parameters, so the schema carries the semantics and baseline 3 applies. Notably the description says 'username and password' while the schema requires 'email', a small terminology mismatch that could confuse an agent about which identifier to send.

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 (login) and the outcome (receive a session token), which is more than a restatement of the name. It does not distinguish itself from nearby siblings such as immich_create_session, immich_shared_link_login, or immich_maintenance_login, so an agent cannot tell from the text which login path applies.

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?

There is no when-to-use guidance, no prerequisites (does the caller need a server URL, a first-time setup, an unauthenticated context?), and no mention of alternatives among the several login/session siblings. Usage is only implied by the credential-exchange nature of the tool.

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