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

Annotations already cover read-only, idempotent, and non-destructive behavior. The description adds useful behavioral context beyond those annotations: the result is ordered by usage, reflects actual event names in the user's PostHog, and depends on PostHog being connected. This is meaningful for an agent deciding whether the tool will work in a given context.

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?

Three short sentences with no filler: the core function is first, followed by a practical usage directive and a necessary precondition. Every sentence earns its place and the most important guidance 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?

For a simple listing tool with no output schema, the description covers what the tool returns (event names, ordered by usage), when to use it, and a key environmental requirement (PostHog connected). Required parameters are documented in the schema, and nothing essential for correct invocation 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?

Schema description coverage is 100%, so the schema already documents limit, search, and companyId fully. The description does not add parameter-level semantics beyond what the schema provides, so the baseline score of 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 uses a specific verb ('List') with a clear resource ('all event types tracked in PostHog') and states the ordering ('by usage'). This distinguishes it from sibling tools like posthog_list_insights, posthog_query_funnel, and posthog_query_trends without needing to inspect 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 explicitly tells the agent to call this FIRST before building funnels or trends, providing a clear and useful usage context. It also states the precondition that PostHog must be connected. It does not mention what to do when PostHog is not connected or name an alternative tool, so it falls just short of full when/when-not guidance.

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