browser_tab_list

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

The annotation readOnlyHint=true already declares this is a safe read operation. The description adds the detail that it lists tabs and the active stable page ID, which hints at the return structure but provides no further behavioral traits such as handling of empty tab lists or session validity. No contradiction with annotations.

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, front-loaded sentence that communicates the tool's core purpose without any redundant words. Every part of the sentence contributes meaning.

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 the tool's simplicity (one optional parameter) and the readOnlyHint, the description covers the essential purpose and the key output. However, since no output schema exists, the description does not fully specify what information is returned for each tab (e.g., URL, title, ID), leaving some ambiguity for the agent about the response structure.

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 only parameter, sessionId, has 100% schema description coverage, so the schema already explains its meaning. The description's mention of 'automation session' aligns with this but does not add new semantic detail 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 uses the verb 'List' with the resource 'tabs' and specifies the additional output of the active stable page ID, distinguishing it from sibling tab operations like browser_tab_new, browser_tab_select, and browser_tab_close. However, the phrase 'tabs and the active stable page ID' is slightly ambiguous about whether the active stable page ID is part of the tab list or a separate return value.

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 no explicit guidance on when to use this tool versus alternatives, nor any exclusions. It only says 'for an automation session,' which is general context inherited from the sessionId parameter, not a directive for tool selection.

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