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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is known. The description adds one genuinely new behavioral fact: PII in returned data is hashed. It does not cover the default two-hour time window, sample limits, or result shape, which matters for a read with no output schema.

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?

Two short sentences with no filler, and the core capability is front-loaded. It is arguably too terse for a 10-parameter tool, but 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 10-parameter tool with no output schema, the description leaves major gaps: how source_id relates to tracking_plan_id/tracking_plan_version, what the default time window is, and what the sample-event flags return. An agent must read the entire schema to call it correctly.

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 70%, and the schema already documents start, event_name/event_type pairing, max_samples, and the sample flags. The description only echoes 'optional sample events' and adds that samples are hashed; it says nothing about workspace_id, tracking_plan_id, or tracking_plan_version semantics.

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 names a specific verb and resource: retrieving tracking plan validation failures with violation details. It implicitly distinguishes itself from the metrics sibling by focusing on 'validation failures' rather than metrics, but it does not name that sibling or otherwise explicitly differentiate.

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 guidance on when to use this tool versus alternatives such as get_source_tracking_plan_event_metrics, list_tracking_plan_events, or get_source_event_schemas. Prerequisites, like whether tracking_plan_id or tracking_plan_version must be supplied even though they are not marked required, are not addressed.

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