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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds meaningful context beyond annotations by flagging the operational prerequisite that PostHog must be connected, plus the intended audience of the operator or analytics agent.

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 compact and front-loaded: it states the core action first, adds a helpful parenthetical definition, then gives usage guidance and a prerequisite. 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 low-complexity list tool with rich annotations and a fully documented schema, the description is nearly complete: it explains what the tool lists, who it is for, when to use it, and the connectivity requirement. It does not describe return shape, but the 'List' verb makes the outcome reasonably implicit.

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 limit, search, enabled, companyId, and scanner_type. The description does not add parameter-level meaning, but with full schema coverage the baseline of 3 is appropriate; it does not need to compensate.

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 a specific verb and resource: 'List Replay Vision scanners' in the connected PostHog project. It defines what scanners are ('AI probes that watch session recordings') and its exact scope, making it easy to distinguish from PostHog event/insight listers and from create/update/delete scanner 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 clear when-to-use instruction: 'Use when checking which scanners exist before creating or updating one.' It also states a prerequisite: 'Only works if PostHog is connected.' However, it does not explicitly name alternatives or explain when not to use this tool, so it falls short of a 5.

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