serial.read

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

No annotations are provided, so the description carries full burden. It discloses that the read is non-blocking ('Returns immediately') and bounded by a timeout and nbytes. However, it does not specify error behavior (e.g., on timeout or invalid connection) or the exact return format, which are important for a read operation.

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?

The description is concise at two sentences, with the purpose front-loaded and the alternative guidance efficiently placed. Every sentence adds value without 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?

Given four parameters and no annotations or output schema, the description lacks important context: it does not mention the return type (string in text/hex/base64), the required open connection, or error scenarios. This leaves significant gaps for an agent to use the tool 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 coverage is 75%, but the description only reiterates 'nbytes' from the schema ('Read up to nbytes'). It adds no explanation for connection_id, timeout_ms, or the 'as' format parameter, leaving the agent to rely solely on schema descriptions for these.

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 verb 'Read' and the resource 'serial port', specifying behavior 'Returns immediately with whatever data is available within the timeout.' It distinguishes from sibling tools serial.readline and serial.read_until by naming them explicitly for line-oriented reads.

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 explicit guidance to use alternative tools for line-oriented reads ('Use serial.readline or serial.read_until for line-oriented reads.'), which helps in selecting the right tool. However, it does not explicitly state when not to use this tool (e.g., when line-based reading is needed).

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