pin_history

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

With no annotations, the description carries the full burden and does well: it discloses ordering (newest first), the default full-record return, the projection semantics of 'fields', and the size trade-off. It omits permission/auth requirements and any pagination or history-length limits, which would matter for an audit tool.

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?

Purpose and ordering are front-loaded, and the parameter behavior follows logically. It is somewhat long with some redundancy around bodies dominating size, but nearly every sentence adds operational value.

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 explanation is not required, and the no-annotation case is largely covered by the behavioral and parameter detail given. Only minor gaps remain (auth/permissions, pagination limits) for a history/audit tool.

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 0%, so the description must compensate, and it does: it enumerates the projectable field names and the special 'headers' string value, and states the default behavior when 'fields' is omitted. 'key' itself gets no explanation beyond the schema's required constraint.

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?

States a specific verb+resource ('Full version history of a pinned entry by key, newest first') and immediately frames the purpose as an audit of who changed it and when. An agent can distinguish it from pin_get/pin_list/message_history without opening any schema.

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?

Gives explicit when-to-use ('Use it when a listing over a long history would otherwise be too large to return') with the rationale that bodies dominate size, plus the follow-up alternative (fetch the ones you want individually afterwards). It stops short of naming sibling tools like pin_get or message_history, so routing is inferential rather than fully spelled out.

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