Retrieve distinct service names from log records in a specified UTC time window, sorted alphabetically, to identify which services emitted logs.
Distinct service.name values attached to log records inside the given UTC window. Sorted alphabetically.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | Window end (ISO-8601 UTC). Required, > from. | |
| from | Yes | Window start (ISO-8601 UTC). Required. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover readOnlyHint and idempotentHint, so the bar is lower, and the description still adds genuinely useful behavior: results are de-duplicated ('distinct') and deterministically ordered ('sorted alphabetically'). It omits edge-case behavior such as what happens with an empty window or whether the list is capped, keeping it short of a 5.
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?
Two short sentences, front-loaded with what is returned before the ordering detail. Every clause carries information; nothing is repeated from the schema or annotations.
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 two-parameter read-only listing tool with no output schema, the description effectively characterizes the return value (distinct service names, alphabetical) so an agent knows what it gets. Minor gaps around empty-result and list-size behavior are the only missing pieces.
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 both parameters are fully documented (ISO-8601 UTC, to > from). The description only restates that the pair forms a UTC window, adding little beyond the schema, so the baseline 3 applies.
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 the exact resource ('distinct service.name values') and scopes it to log records inside a UTC window, which implicitly separates it from list_metric_services and list_trace_services. It doesn't explicitly name those siblings, so differentiation is inferable rather than stated.
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?
Usage is only implied: the window scoping suggests this is a discovery/enumeration tool to run before query_logs, but the description never says when to use it, when not to, or what alternative to pick. An agent must infer the discovery workflow from the return shape alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.