janus_login

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

Annotations only cover safety hints (readOnly=false, openWorld=true, destructive=false, idempotent=false). The description adds material behavior beyond that: a browser window opens, the token is captured locally and saved to the OS keychain, and it never passes through the chat. This is exactly the security-relevant context an agent needs.

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 tight sentences: action first, token-handling detail second, provider list last. No filler, and the most decision-relevant information is front-loaded.

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?

No output schema exists, so the description carries the return-value burden, which it does by explaining the token is saved locally and how to reference it afterwards. Combined with 100% schema coverage, an agent has everything needed to invoke it correctly.

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 both parameter descriptions already explain 'name' (used as oauth:<name>) and 'provider' (preset, e.g. github, google). The description largely restates this convention rather than adding new syntax or constraints, so baseline 3 applies.

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+resource (start OAuth login for a provider) and the side effect (store token as <name>). It is clearly distinguishable from siblings like janus_list_accounts or janus_whoami, which do not initiate auth flows.

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?

Tells the agent the follow-up step: reference the token via an account env as "oauth:<name>", and lists built-in providers (github, google, supabase). It gives clear context for when this tool is the right one, but doesn't explicitly state when not to use it or prerequisites (e.g., whether a browser must be available).

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