Login to Bridge

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

Annotations already declare readOnlyHint=false and destructiveHint=true; the description adds genuinely new behavior: credentials come from PROTON_BRIDGE_PASS or a password store, the password never passes through the caller, and only metadata is returned. It does not address why destructiveHint is true (session replacement, 2FA, failure modes), which is the one annotation an agent would want explained.

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 tightly written sentences with no filler; the core action is first and the security-relevant constraint ('password never travels through you') follows immediately. Every clause carries information an agent needs.

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 no-arg tool with no output schema, the description covers credential source and return-value scope ('metadata only'), which is most of what an agent needs. It omits failure/side-effect context such as whether an existing session is invalidated or what a failed login means, a noticeable gap given the destructiveHint annotation.

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?

With zero parameters the baseline is 4, but the description goes further by explaining where the credential is sourced from and why no arguments are accepted, which is information the empty schema cannot convey. That fully compensates for the schema's silence.

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 ('Logs in to Proton Mail Bridge') plus the credential source ('configured on this machine'), so the action is unambiguous. It never names or contrasts the nearest siblings (proton_bridge_status, proton_bridge_logout, proton_drive_auth_login), so sibling differentiation is left to inference.

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 implied by the credential-source sentence - this is the tool that establishes a Bridge session - but there is no explicit 'call this when X, not Y', no prerequisite ordering (e.g., check proton_bridge_status first), and no guidance about an existing session. An agent can infer the context but is not told when to prefer alternatives.

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