GET a PostHog API endpoint

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful behavioral context: the {project_id} path placeholder is replaced with the default project, which is a non-obvious behavior. It does not describe response format, but with no output schema and a generic GET tool, the description provides adequate transparency beyond annotations.

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 two sentences with no wasted words. The primary purpose is front-loaded, the scope boundary is stated immediately, and the {project_id} substitution detail is placed at the end where it belongs. Every sentence earns its place.

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 generic GET-all-endpoints tool with readOnlyHint=true and openWorldHint=true, the description covers the essential context: what it does, when to use it, and the key path substitution behavior. It does not explain response format or error behavior, but for a passthrough GET tool with no output schema, this is a minor gap. The sibling tools are not explicitly differentiated, but the HogQL contrast helps.

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 both parameters (path and params). The description adds the important detail that {project_id} in the path is replaced with the default project, which adds meaning beyond the schema. However, it does not elaborate on the params object structure beyond what the schema provides, so a 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 states a specific verb ('GET') and resource ('any PostHog REST endpoint'), and explicitly scopes it to what HogQL does not cover, listing concrete examples (feature flags, insights, dashboards, experiments, cohorts). This clearly distinguishes it from sibling tools like posthog_query, which presumably covers HogQL.

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 on when to use this tool ('for what HogQL does not cover') and lists example endpoints. It does not explicitly name sibling alternatives or state when not to use it, but the contrast with HogQL and the sibling list (posthog_query) makes the usage context reasonably clear.

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