Selects the successful run according to a metric and min/max mode, optionally restricted to one step.
Find the best succeeded run by a metric.
| Name | Required | Description | Default |
|---|---|---|---|
| mode | No | 'min' for losses/errors, 'max' for scores | max |
| step | No | Restrict to one step | |
| metric | Yes | Metric name, e.g. 'val_rmse' or 'roc_auc' |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.4.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of behavioral disclosure. It does disclose that only succeeded runs are considered and that selection is metric-based, but it omits tie-breaking behavior, permission requirements, and whether 'succeeded' has any special semantics.
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 a single front-loaded sentence with no wasted words. It is appropriately brief for a tool whose schema and output schema carry most of the structural detail, though it could provide slightly more framing around the key qualifier 'best'.
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?
The tool is simple, with full schema coverage and an output schema, so the description does not need to explain parameters or return values. However, with no annotations, it remains incomplete on behavioral details such as tie handling and permission expectations.
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 description coverage is 100%, so metric, mode, and step are already well documented. The description mentions the metric concept but adds no syntax or usage detail beyond what the schema provides, making the baseline 3 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 states a specific verb and resource: find the best succeeded run by a metric. It is understandable without opening the schema, but it does not differentiate itself from list_runs or explain what 'best' means, so it falls short of full sibling-level clarity.
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?
There is no explicit guidance on when to use this tool versus list_runs or other siblings. The phrase 'Find the best succeeded run' implies the use case, but no alternatives, prerequisites, or exclusions are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.