bridge_probe

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

With no annotations, the description carries the burden and does well: it declares the operation is non-invasive (does not touch any bus, pure handshake) and explains the port-resolution fallback to MCU_DEBUG_BRIDGE_PORT. It omits any auth/permission note and does not restate the baudrate behavior, but for a read-only probe this is minor.

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?

Front-loads the core definition, then the diagnostic rationale and the port/env detail. Several lines are spent on troubleshooting motivation, but each sentence adds routing or parameter value; no obvious filler.

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. For a simple 2-param, no-required probe the description covers purpose, when-to-use, and the key port fallback; only baudrate behavior is left undocumented.

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% for 2 parameters, so the description must compensate. It explains the port fallback via the MCU_DEBUG_BRIDGE_PORT environment variable, which is genuinely useful, but says nothing about baudrate or its default semantics.

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 action (handshake / self-check with the bridge firmware) and its scope ('不碰任何总线，纯握手'), which immediately separates it from the many bus tools (i2c_scan, spi_scan, serial_*). An agent can tell what it does and what it does not touch without opening any schema.

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?

Gives explicit usage context: it is the first step when 'bus tools aren't working' — confirm the bridge is alive before suspecting wiring. It frames the diagnostic order clearly but does not name a concrete alternative sibling (e.g. probe_list or serial_list) to choose against.

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