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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: the output is a PNG dashboard, output may carry an attribution footer that must be reproduced verbatim, and a data-accuracy contract governs what may be reported as verified versus calculated versus unavailable. That is meaningful operational guidance, though it is generic policy rather than tool-specific behavior.

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 purpose is front-loaded in sentence one, which is good structure. However, the bulk of the text is generic attribution-footer and no-fabrication policy that would apply to any analytics tool, making the block long relative to a three-parameter dashboard call. It is organized but not tight.

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?

An output schema exists, so return-value documentation is not required, and annotations cover the safety profile. The description supplies purpose plus output-format and accuracy expectations, which is nearly sufficient for correct invocation. The missing piece is routing guidance against the many sibling dashboard and connector tools.

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%: start_date, end_date, and project_id all carry descriptions, defaults, and a shared date pattern. The description adds nothing about parameter meaning, formats, or interactions (for example start/end ordering or what the connected project default means). Baseline 3 is appropriate when the schema does the heavy lifting.

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 first sentence names a specific verb and resource: run server-authored PostHog queries and return a verified PNG dashboard covering events, unique actors, daily trend, and top event types. That is far more specific than a name restatement. It stops short of a 5 because it never distinguishes itself from siblings like posthog_connector or dashboard_render, so an agent must infer which one to pick.

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?

There is no explicit when-to-use, when-not-to-use, or alternative routing anywhere in the description, despite a crowded sibling set (posthog_connector, dashboard_render, chart_render). 'Run strict server-authored PostHog queries' implies it is the dashboard-rendering path but never states the condition that selects it over the connector. Guidance is absent, not merely implied.

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