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compare_ros_topics

Read-onlyIdempotent

Compares two ROS 2 topics by sampling both for a set duration, then matching messages one-to-one via exact or tolerance timestamp alignment in compatible clock domains.

Instructions

Simultaneously sample two topics, require explicit compatible clock domains, then one-to-one exact/tolerance match. Sampling phase is not physical clock offset.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
topic_aYes
topic_bYes
strategyNoexact
duration_sNo
tolerance_nsNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
dataNo
errorNo
sourceYes
statusNovalid
warningsNo
measurementsNo
schema_versionNo1.0
observed_at_utcNo
measurement_kindNoobserved

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

B3.2/5.0
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so safety is covered. The description adds a genuinely useful caveat that the sampling phase is not a physical clock offset, plus the clock-domain compatibility requirement, but it never says what happens when domains are incompatible or that the call is time-bounded.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two dense sentences with no filler, and the action is front-loaded before the caveat. The final sentence is terse to the point of being cryptic, but it is information-bearing rather than padding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

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 explained. However, for a sampling-and-matching tool with a duration budget and a tolerance parameter, the description omits how long it blocks and how tolerance interacts with the strategy, leaving real gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% across 5 parameters, so the description must carry the load. It names the two topic inputs and both strategy enum values, but says nothing about duration_s (a bounded sampling window, max 30s) or tolerance_ns (nanosecond tolerance used with the tolerance strategy), leaving the two numeric knobs entirely undocumented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific action and resource: sample two ROS topics simultaneously and perform a one-to-one exact/tolerance match. It is clearly distinct from siblings like analyze_ros_timestamps or list_ros_topics, though it does not name those alternatives explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'require explicit compatible clock domains' functions as an implied precondition for use, but there is no explicit when-to-use/when-not guidance and no routing to a sibling such as analyze_ros_timestamps for non-paired analysis.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.