session_list_pages

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

With no annotations provided, the description carries the burden of behavioral disclosure. It clearly states what the tool returns and notes a meaningful limitation about the id alone. A small gap is that it doesn't explicitly state read-only behavior, but the verb 'list' reasonably implies a non-mutating operation.

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?

Two compact sentences, with the essential output contract front-loaded and the usage guidance in the second sentence. Every sentence earns its place with no filler or 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?

For a zero-parameter list operation with an output schema available, the description covers everything an agent needs: the scope of results, the fields returned, and the recommended usage ordering relative to session_select_page. Nothing important is missing.

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 and the schema is already fully descriptive, so the description couldn't add much parameter-level detail. It instead adds value by explaining the output fields and how they relate to subsequent tool usage, which is appropriate for a parameterless tool.

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 identifies a list operation over open tabs with specific output fields (id, title, url, active state). It also distinguishes itself from session_select_page by explicitly naming it, so an agent can tell them apart without inspecting schemas.

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 contextual guidance: use this tool before session_select_page because the tab id alone doesn't indicate which tab you're switching to. This tells the agent not just what the tool does, but when to call it relative to a sibling.

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