x_session_open

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

Annotations already indicate this is a write-like operation (readOnlyHint=false) and not idempotent. The description adds value by specifying that it opens a browser profile or tab and that user sign-in is manual, which is critical for an agent to set expectations. This goes beyond the annotations without contradicting them.

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 and reasonably compact. It states the core action and a key nuance about CDP, but the second sentence about manual sign-in is somewhat tangential and could be condensed. Overall, it is well-structured and 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?

For a zero-parameter tool with no output schema, the description is mostly complete. It covers what the tool does and the manual sign-in aspect. However, it lacks details on what the agent should do after calling it (e.g., wait for user input) or how the session is identified. Given the complexity is low, a score of 3 reflects the minor gap in usage flow.

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 tool has zero parameters, so the schema provides no parameter semantics. The description mentions the browser profile and CDP browser, but it does not add detail on how to specify those. Since there are no parameters, the baseline is 4, but the description's vagueness about configuration reduces it to 3.

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 states a specific verb ('Open') and resource ('a dedicated browser profile'), which distinguishes it from sibling session tools like x_session_status and x_session_close. However, it is somewhat ambiguous because it also mentions opening a new tab in a CDP browser, which could be a different operation, and it doesn't clarify the primary purpose compared to other session-related tools.

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 a brief context for when to use the tool (to open a session before user manual sign-in), but it does not explicitly state when to use it over alternatives like x_session_status or x_session_close. The mention of 'explicitly configured CDP browser' hints at a condition, but there is no clear differentiation from siblings.

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