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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description adds genuinely non-obvious context beyond them: rules are returned exactly as saved, enabling a lossless round-trip into update_segment. It does not mention behavior for a nonexistent ID, but that is a minor omission given annotation coverage.

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 sentences, front-loaded with the return payload and closed with the ID-discovery hint. No filler or redundant restatement of the title.

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 one-parameter read tool with full annotation coverage and no output schema, the description covers what is returned, why the exact-saved format matters, and where to get the ID. Nothing an agent needs to invoke it correctly is missing.

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's schema description already says "Segment ID from list_segments," which the description merely restates. Baseline 3 applies since the schema does all the work and no additional format or validity constraints are offered.

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 ("Show one segment's full definition") and enumerates exactly what is returned: name, match mode (all/any), lists, contact count, and every rule. This clearly distinguishes it from list_segments and from the mutation sibling update_segment.

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?

It gives a concrete entry path ("Find the ID with list_segments") and implies the downstream use case by noting the rules can be passed to update_segment. It stops short of explicit when-not guidance, but for a single-record getter the routing is unambiguous.

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