pulse_atFetch the NIST Randomness Beacon pulse closest to a given Unix timestamp in milliseconds (time_ms); returns the 512-bit output value and chain/signature metadata.
| Name | Required | Description | Default |
|---|---|---|---|
| time_ms | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| pulse | No | Pulse data object | |
| statusCode | No | HTTP status code |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "time_ms": 1704067200000
+ }
+]Output schema / (root)Previous value: -nullNew value: +{
+ "properties": {
+ "pulse": {
+ "description": "Pulse data object",
+ "type": "object"
+ },
+ "statusCode": {
+ "description": "HTTP status code",
+ "type": "integer"
+ }
+ },
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate the tool is read-only and safe. The description adds behavioral detail: it returns the 'closest' pulse along with metadata, which is beyond annotation scope. No contradictions.
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 of 20 words that efficiently conveys the action, resource, input, and output. No fluff or redundancy.
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 description covers purpose, input format, and output summary. With an output schema present and comprehensive annotations, the description is largely sufficient, though it omits potential error conditions or range constraints.
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?
With 0% schema coverage, the description clarifies that time_ms is a Unix timestamp in milliseconds and that the tool finds the closest pulse. This adds meaning beyond the schema's type and required flag.
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 clearly states the tool fetches the NIST Randomness Beacon pulse closest to a given Unix timestamp, specifying the input format and output contents. It implicitly distinguishes from siblings like 'last_pulse' and 'latest_in_chain' by focusing on historical lookup.
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?
The description provides context for when to use the tool (fetching a pulse near a specific timestamp) but does not explicitly exclude alternatives or compare with sibling tools, leaving the agent to infer usage boundaries.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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