foto_login

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

With no annotations, the description carries the full behavioral burden. It does usefully disclose that credentials are stored locally and securely, which is a real behavior beyond the schema. It omits what happens on failure (bad credentials), whether an existing session is replaced, and whether the stored credentials persist across calls.

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?

Two short sentences with zero waste. The action is front-loaded and the storage behavior follows immediately as supporting context.

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?

There is no output schema and no annotations, so the description should say what a successful call yields (session established? token?) and what errors an agent should expect. It covers the input side adequately but leaves the result side blank, which matters for an auth entry point that other tools depend on.

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%, and both parameters (email, password) are self-documented with formats and constraints, so the baseline of 3 applies. The description adds nothing about credential semantics — e.g., whether the email must match a pre-existing Foto account — beyond what the schema states.

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: 'Authenticate with Foto app' using email and password. That is clearly distinguishable from foto_logout and foto_auth_status, though the description never names those siblings to reinforce the split.

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 only implied — an agent can infer this is the entry point when credentials are needed. There is no explicit guidance on when to call it versus foto_auth_status (checking an existing session) or foto_logout, and no statement about whether it must precede the other Foto tools.

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