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

There are no annotations, so the description carries the burden of disclosing behavior. It adds one useful trait: returned messages are "after any formatting done during processing," signaling that the history may not be raw. However, it does not mention ordering, pagination, read-only semantics, or permissions, leaving some behavioral gaps.

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 compact, with the main action stated first. Each sentence earns its place: the first defines the operation, the second clarifies message formatting, and the third gives the practical use case. There is no redundant filler.

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 simple one-parameter tool with no output schema, the description is mostly sufficient: it states what is returned, notes post-processing formatting, and explains why the tool would be used. It could be slightly stronger by describing the return structure or ordering, but nothing critical blocks correct invocation.

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%, and the only parameter, sessionId, is already clearly documented in the schema. The description does not add meaning beyond the schema, so the baseline score of 3 is appropriate.

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 uses a specific verb and resource: "Retrieve the full message history for a session." This clearly distinguishes it from the sibling tools, which are about asking experts or verifying answers rather than retrieving past conversation content.

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?

"Use to resume discussions" gives a clear, practical scenario for when this tool is appropriate. It does not explicitly name alternatives or exclusion criteria, but the intended usage is understandable without further elaboration.

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