mattermost_login

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

With no annotations at all, the description must carry the full behavioral burden. It does disclose meaningful behavior: a one-time pairing, a session token handed off over SSH to a local Login Helper, and that the provider is decided by the Mattermost site config. It does not say whether the call mutates account/session state, how long the pairing or token lives, or what happens if pairing fails.

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?

Three short sentences, front-loaded with the core action and its return value, then the conditional parameter rule, then the provider note. Dense and purposeful, with no filler, though the provider sentence sits last and reads as an afterthought.

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 the description does at least say a value is returned (an npx command), which is helpful. But for a login tool with zero annotations, missing side-effect disclosure, token lifetime, and post-login verification steps leaves the agent guessing about what to do once the command is returned.

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% and the sshTarget property already documents 'SSH alias or user@example.com; omit when MCP and browser are on the same machine'. The description's explanation is essentially the same rule restated, adding no new syntax, format, or failure semantics beyond the schema.

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 concrete verb and outcome: 'establish a one-time login pairing and return an npx login command'. This is clearly a different action from the sibling mattermost_auth_status, though the description never names that sibling to make the distinction explicit.

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 remote-vs-local condition ('specify sshTarget when MCP is remote, omit when on the same machine') is stated clearly, which is a real usage rule. However, there is no guidance on when to call this at all versus checking mattermost_auth_status first, and no mention of prerequisites or follow-up steps.

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