Sign In

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

Annotations already indicate mutation (readOnlyHint=false). The description adds the specific behavioral trait of setting session cookies, which explains the mechanism and prerequisite nature beyond the annotation. It does not cover edge cases like session expiry or invalidation, but the core behavior is disclosed.

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 a single sentence with two concise clauses, front-loading the main action and quickly stating the side effect. No filler or redundant information.

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 simple two-parameter authentication tool with an output schema, the description provides the essential purpose and side effect. It lacks explicit mention of session duration or behavior on repeated sign-in, but given the low complexity and output schema presence, it is adequately complete.

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%, so the schema already documents both parameters (email and password) with descriptions. The tool description adds no additional parameter semantics, but the baseline of 3 is appropriate given full schema coverage.

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 clearly specifies the action ('Sign in to AFFiNE'), the method ('using email and password'), and the resource (AFFiNE). It also mentions the side effect of setting session cookies, which distinguishes it from all sibling tools that operate on workspaces and docs.

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 implies this is a prerequisite for subsequent calls by stating it 'sets session cookies for subsequent calls,' providing clear context. There are no alternative sign-in tools among siblings, so no explicit when-not-to-use guidance is needed.

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