Diff an entity's history

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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds valuable behavioral context: newest-first ordering, dotted-prefix matching scope, and the derived `superseded_by` id with empty-string semantics for the latest event. No contradiction with 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 concise and front-loaded: the first sentence gives the core purpose, and the second provides high-value examples of prefix matching and derived data. Every sentence earns its place with no redundancy.

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?

Given the output schema and safety annotations, the description sufficiently covers the essential behavior: ordering, prefix semantics, and the derived superseded_by trail. It does not discuss sibling-tool selection, but the core functionality is thoroughly described.

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?

The input schema covers both parameters fully (100% coverage), so the baseline is 3. The description restates prefix matching with an example but does not add new parameter-level semantics beyond what the schema already documents.

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 returns change history for a codebase entity, newest first, and highlights unique behaviors like prefix matching and the derived `superseded_by` field. However, it does not explicitly differentiate from the similarly-named sibling tool `history`, so it stops short of full sibling distinction.

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 intended use is implied: call this when you need a chronological change history for an entity, especially with prefix matching. But the description does not compare this tool to alternatives like `history` or `blame`, nor does it mention exclusions or when not to use it.

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