ancestry_session

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

The description discloses that 'login' opens a Chrome window, waits for user sign-in, saves cookies, and closes Chrome. Saving cookies is a write operation that modifies session state. However, the annotations declare readOnlyHint: true, which implies the tool does not modify data. This directly contradicts the described behavior. Therefore, the description contradicts the annotations, warranting a score of 1.

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 sentences long, front-loaded with the session purpose, and each sentence earns its place. It is concise without unnecessary detail, and the critical usage instruction ('run it only when status says not logged in') is included.

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 tool with two parameters and no output schema, the description covers both actions and their purpose. It explains that 'status' reports session validity and user identity, and 'login' handles the sign-in flow. The missing piece is explicit output format for 'status', but the description states what it reports, which is sufficient for an agent to call 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?

The description explains the meaning of the two actions, which is not fully covered by the schema (the 'action' parameter has an enum but no descriptive text). The 'timeoutSeconds' parameter is already described in the schema. With schema coverage at 50%, the description compensates by clarifying the action values, adding value 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?

The description clearly states the tool's purpose: managing an Ancestry login session. It specifies two concrete actions, 'status' and 'login', and explains what each does. It is distinguishable from sibling tools like 'tree', 'person', or 'fact', which handle data operations rather than session management. The verb 'login session' is specific and 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 gives explicit guidance for when to run 'login': only when status says not logged in. It also notes that normal use does not require a browser, implying 'status' is the common operation. It does not explicitly mention alternatives, but sibling tools are unrelated, so the usage context is clear. The exclusion ('run it only when...') is a strong guideline.

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