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mcp_sensor_read

Read sensor values from a remote GPIO agent via mcp-bridge, either all configured sensors or a specific one by name.

Instructions

Read sensors on agent. With no name, reads every configured sensor and returns them merged into one JSON object; with a name, reads just that sensor. Every reading is nested under its sensor's own name: a script emitting a JSON object with several fields nests whole, one emitting a single-field object contributes just that field's value, and any other output is wrapped the same way.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
nameNo
agentYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.9.23

TDQS

A3.6/5.0
Behavior3/5

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

No annotations are provided, so the description carries the full burden. It details the return-shape semantics (nesting rules) which is valuable, but omits error handling, whether readings trigger any device activity, and any auth/permission requirements.

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?

Front-loaded with the purpose, then the two modes, then the nesting rules. Well-structured and efficient, though the nesting explanation is dense and could be terser.

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

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only sensor tool with no output schema, the description covers the input semantics and the return shape well. Missing only ancillary details like error cases or side effects, which limits it from a 5.

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

Parameters4/5

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

Schema description coverage is 0%, so the description must compensate. It explains the meaning of `name` (which sensor to read) and `agent` (target), clearly stating the no-name fallback behavior. Adds real value over the bare schema.

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?

Clear verb+resource: 'Read sensors on `agent`'. States the two operating modes (all sensors merged versus a single named sensor). Reasonably distinguishable from mcp_sensor_config, though it doesn't explicitly name that sibling.

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?

Explains the behavior difference between providing `name` and omitting it, which implicitly tells the agent when to use each mode. However, it does not name alternatives or state exclusions (e.g., contrast with mcp_sensor_config for setup).

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