Set how many days to retain traces before archiving. Configure retention_days to manage local trace storage.
Set the trace retention policy (how many days to keep traces before archiving). Example: { "retention_days": 30 }
| Name | Required | Description | Default |
|---|---|---|---|
| retention_days | Yes | Number of days to retain traces before archiving. Must be > 0. |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations declare readOnlyHint=false and destructiveHint=false, so the write/non-destructive profile is already covered. The description earns partial credit by disclosing what actually happens to expired traces ('before archiving'), which clarifies that data is archived rather than deleted. It says nothing about permissions, reversibility, or effect on traces already past the threshold.
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?
One sentence plus a minimal example, with the core action front-loaded and no filler. Every element carries 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-required-parameter tool with a fully documented schema and no output schema, the description is nearly sufficient. The remaining gap is the missing distinction from 'apply_retention', which an agent selecting between siblings would need.
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% and the schema already states the unit, meaning, and the '> 0' constraint more precisely than the description does. The example object adds usage syntax but no semantic detail beyond the schema's baseline 3.
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?
States a specific verb and resource ('Set the trace retention policy') and clarifies the resource with a parenthetical definition of retention. It does not differentiate itself from the near-identical sibling 'apply_retention', so an agent cannot tell them apart from the description alone.
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 statement of when to use this tool versus alternatives, which matters because the sibling list contains 'apply_retention', a plausible-looking duplicate. The example payload shows invocation syntax but gives no conditional guidance or prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.