canvas_login

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

With no annotations, the description carries the full behavioral burden and does well: it discloses that a Chrome window may open, that the user must complete SSO and MFA, that the session is saved, and that a silent refresh often avoids the window. It does not mention failure modes, timeout behavior, or exactly when the window will appear, leaving minor gaps for a login tool.

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?

The description is two tight sentences with zero waste. The core purpose is front-loaded, followed by necessary operational detail. Every phrase earns its place without unnecessary repetition.

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?

Given no annotations and no output schema, the description adequately covers the interactive login flow and session persistence. The only missing piece is any mention of the timeout parameter, which is the sole input and affects behavior. For a simple login tool, this is largely complete but not fully comprehensive.

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?

The single parameter 'timeout_seconds' has 0% schema description coverage, and the description does not mention it at all. The agent receives no guidance on what the timeout controls or how to set it, so the description fails to compensate for the missing schema documentation.

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?

The description begins with a specific verb and resource: 'Sign in to Canvas.' It explains the mechanism and outcome, and makes clear this is an authentication prerequisite for other tools ('session is saved for the other tools'). No sibling tool covers login, so this is unambiguous.

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 description provides clear context: it is the sign-in tool and its session benefits other tools. It also notes that it 'tries a silent refresh first,' implying it can be called even when a session may exist. However, it does not explicitly state when not to use it or name alternatives, which keeps it from a 5.

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