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

Beyond the readOnlyHint annotation, the description discloses ordering (newest first), append-only nature, pagination semantics (next_cursor null on last page, total_count ignores pagination), and explicitly states that detailed before/after state is never returned. This gives the agent accurate expectations for the tool's 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 most important fact (what the tool reads and ordering) is front-loaded, and every subsequent sentence adds operational value: entry fields, use cases, filters, pagination, and the before/after caveat. No filler or repetition of the schema.

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, zero-required-parameter tool with an output schema, the description covers purpose, filtering, pagination, and output semantics. It gives an agent everything needed to decide to call it and to invoke it correctly, and the output schema covers return structure.

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 coverage is 100%, so the baseline is 3. The description adds value beyond the schema by explaining the cursor continuation contract ('next_cursor as cursor; next_cursor is null on the last page'), clarifying how filters combine, and giving a concrete entity_type example. All five parameters themselves are already documented in the schema.

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?

Description opens with a specific verb and resource: 'Reads the append-only audit trail for an organisation, newest first.' It details the exact entry shape (action, entity_type/entity_id, actor_type, reason, created_at), which makes the tool's purpose unmistakable and differentiates it from transaction- or balance-reading siblings.

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 explicit use cases ('who approved this', 'what happened to event X', 'what has the pipeline done recently') and filter guidance (entity_type/entity_id). It does not name sibling alternatives or state when not to use this tool, so it misses full exclusion guidance but is otherwise clear.

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