session_health

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

With no annotations, the description carries the behavioral burden. 'Check' signals a non-mutating inspection, and it specifies what is inspected (extension health and API availability) and the context ('connected session'). It does not explicitly guarantee a read-only profile or describe failure behavior, but for a zero-parameter diagnostic this is reasonably transparent.

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?

A single front-loaded sentence with no filler. The action, subject, and scope are all present, and every word contributes to the 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?

For a simple, parameterless health check, the description is largely complete: it names both the action and the information returned. It would be slightly stronger if it mentioned expected failure modes or the response format, but since there is no output schema, those are minor gaps rather than blockers.

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 no parameters and the schema already provides 100% coverage with an empty properties object. With zero parameters, there is nothing for the description to add, so the baseline of 4 applies.

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 a concrete verb, 'Check', and a specific resource: extension health plus browser API availability in the connected session. This clearly distinguishes it from sibling tools like session_navigate or session_evaluate, none of which are framed as health diagnostics.

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?

Usage is implied: an agent should call this when it needs to verify that the extension is healthy or determine which browser APIs are usable before proceeding. It does not explicitly state when not to use it or name alternatives, so the guidance relies on inference.

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