ls_list_runs

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

With no annotations, the description carries the behavioral burden. It discloses default behavior (root-only, 24-hour lookback, limit 50, selected fields) and parameter semantics. It does not explicitly mention that it is read-only, but the operation is inherently non-destructive and the defaults provide useful behavioral context.

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 front-loaded with a concise purpose statement followed by a well-structured, line-by-line argument list. It is slightly long but every line adds value, and the formatting improves readability.

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?

At 7 parameters with 1 required, the description covers all parameter meanings, defaults, and constraints. The presence of an output schema relieves the need to describe return values. The tool is fully specified for an agent to understand when and how to invoke it.

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 description adds substantial meaning beyond the schema, explaining each parameter's purpose (e.g., 'error: Filter by error status - True=failed only, False=successful only, None=all'), with ranges and defaults. This fully compensates for the 0% schema description coverage.

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 'List recent runs from LangSmith (root-only by default)' with a specific verb, resource, and scope. The 'root-only' qualifier distinguishes it from sibling tools like ls_list_children, making the purpose unambiguous.

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 implies usage context (listing recent runs with filtering) but does not explicitly state when to use this tool versus alternatives like ls_list_children or ls_read_run. No exclusions or alternative references are provided.

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