list_tabs

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

With no annotations provided, the description carries the behavioral disclosure burden and does it well: it discloses that the tool checks visibility, that probe requires an extra round trip, and that session ownership may be absent '(if any)'. This gives the agent useful expectations beyond the bare 'list' verb.

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 sentences with no filler: the first delivers the purpose and output fields, the second connects the result to the next step. Every clause adds value, and the most important information is 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?

Given there is no output schema, the description compensates by listing the returned fields explicitly and explains how the index should be consumed. It does not describe output formatting or failure behavior, but for a simple listing tool the critical context is present.

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 description coverage is 100%, so the input schema already documents host, port, and probe. The tool description does not add parameter details, but it also does not need to because the schema already carries that weight. Baseline 3 is appropriate.

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 opens with the specific verb 'List' and the resource 'debuggable tabs in Chrome', then enumerates the exact fields returned: index, title, URL, visible flag, and owning DevCDP session. This clearly distinguishes list_tabs from sibling tools like sessions_list or devtools_connect.

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 clear context for when this tool is useful: when you need the list of tabs and their indices. It also provides direct downstream guidance by instructing the agent to use the index with target:'index:<n>' in devtools_connect. It does not explicitly name alternatives or exclusions, so it misses the top score.

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