ls_list_children

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

No annotations are provided, so the description carries the full burden. It discloses the return shape (list of child run objects with specific fields), the limit parameter with default and range, and the fact that it lists children. Since it's a 'List' operation, it implicitly communicates read-only behavior, but it doesn't explicitly state side effects or auth requirements. Still, it provides useful behavioral details beyond the schema.

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 well-structured with a concise one-line summary, a clear 'Args' section, and a 'Returns' section. Every sentence is informative, no redundant wording, and the most important information is front-loaded.

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?

Given it's a simple listing tool with two parameters and an output schema, the description covers all necessary context: how to call it, what parameters mean, and what kind of objects are returned. It even mentions timing and error info in the return, which is more than many tools provide. The output schema further supplements return details, so nothing essential 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?

The schema only provides types and defaults, but the description adds full semantics: parent_run_id is required, limit is the maximum children and has a valid range (1-500). With 0% schema coverage, the description fully compensates by explaining each parameter's purpose and constraints.

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 starts with a specific verb 'List' and resource 'child spans', scoped to 'a given parent run'. This clearly distinguishes it from sibling tools like ls_list_runs, which lists runs at the top level, and ls_read_run, which reads a single run.

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 states that parent_run_id is required, implying you use this after you have a parent run ID (likely from ls_list_runs). It doesn't explicitly mention alternatives or exclusions, but the context is clear: when you need to inspect children of a specific run.

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