List the variables a selection needs

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

With no annotations provided, the description carries the full burden. It discloses that the tool is read-only ('Reads only') and describes a notable behavior ('a title matching several is refused'). It does not cover permissions or rate limits, but those are less critical for a lightweight read-only list operation.

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?

Three compact sentences with no filler. The primary statement is front-loaded, the rationale follows, and the behavioral caution is brief. Every sentence contributes new, useful information.

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 single-parameter, read-only tool with no output schema, the description covers what it does, when to use it, and an important edge case. It omits details like error handling for invalid clause IDs, but the core invocation and expectation are sufficiently complete.

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 by clarifying that the clause_ids parameter is about 'the clauses you name' and explaining how ambiguity is handled ('a title matching several is refused'). This helps the agent provide a valid input.

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 ('List') and resource ('every variable the clauses you name use') and even explains what is returned (which clause uses each variable). It clearly differentiates from siblings by contrasting with contract_assemble and noting it is read-only.

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 an explicit usage context: run this before contract_assemble leaves bracketed prompts. It does not name alternative tools for when not to use it, but the timing hint and 'Reads only' are enough to guide the agent.

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