Poll newly written spans with a cursor to monitor ongoing agent activity and avoid missing trace data.
Poll newly written spans using a cursor; useful while an agent run is still active.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| cursor | No | ||
| trace_id | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.6.1Does 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 key polling/cursor model, which is genuinely useful behavioral context for an incremental-read tool. However it says nothing about what happens at end-of-stream, whether the cursor is mandatory, or how trace_id scopes results.
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?
A single front-loaded sentence with zero waste: it leads with the operation and tacks on the usage condition. Nothing to trim.
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?
An output schema exists, so return values need not be described, and the polling model is captured. But with 0% schema coverage and no annotations, the two unexplained parameters (limit, trace_id) leave the definition short of what an agent needs to call it correctly.
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 0% and there are 3 parameters. The description explains the purpose of 'cursor' in the polling model but leaves 'limit' and 'trace_id' entirely undocumented in both schema and description, failing to compensate for the coverage gap.
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 ('Poll newly written spans') plus a mechanism ('using a cursor'). The word 'newly' implicitly distinguishes it from the one-shot search_spans sibling, but no sibling is named, so differentiation is left to inference.
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?
'useful while an agent run is still active' gives a clear temporal context for when to reach for this tool, but it names no alternative (e.g., search_spans) and states no exclusions, so the agent must infer the boundary.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.