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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the dependency on PostHog connection and the nature of output (conversion rates), which is useful beyond annotations. However, it does not disclose other behavioral details like data volume limits or error conditions, so it adds some but not rich 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?

The description is two concise sentences that state the purpose and a key prerequisite. It is front-loaded with the core function and contains no unnecessary words. Every sentence is informative and 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 read-only query tool with annotations covering safety and a fully documented schema, the description is nearly complete. It covers the main action and the critical prerequisite (PostHog connection). It doesn't describe return format, but the absence of an output schema makes that a minor gap. The description adequately supports correct invocation.

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 all parameters are documented in the schema. The description itself does not add additional parameter-specific meaning beyond what the schema provides. For example, it doesn't explain how 'funnel_window_days' impacts results or that 'events' requires at least 2 steps. The baseline of 3 is appropriate given the high schema coverage.

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 clearly states the tool's function: 'Build and run a funnel analysis in PostHog' and specifies the output: 'Shows step-by-step conversion rates'. It uses a specific verb (build/run) and resource (funnel analysis) that distinguishes it from sibling tools like posthog_query_trends or posthog_list_events.

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 clearly indicates the tool's purpose and the prerequisite 'Only works if PostHog is connected.' While it does not explicitly contrast with alternatives, the mention of 'funnel analysis' makes its use case clear. It would be improved by naming siblings or specifying when not to use it, but the context is sufficient.

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