ble_write

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

No annotations provided, so description carries full burden. It discloses the need for a configuration variable and two encoding formats. However, it does not describe side effects, failure behavior, or the fact that this is a mutation operation. The with_response parameter's behavior is hinted at in the schema but not elaborated.

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 two sentences long with no extraneous information. It front-loads the primary action and encodes essential constraints efficiently.

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?

No output schema exists. The description does not specify return values or success/failure indicators. It also does not mention that writing requires an active connection or other contextual dependencies, though these may be inferred from tool names.

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 60% (3 of 5 parameters have descriptions). The description adds value by clarifying that value_b64 and value_hex are alternative encodings for the write value, which is not obvious from the schema alone. It does not describe connection_id or char_uuid, but those are standard BLE parameters.

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 'Write a value to a GATT characteristic', a specific verb-resource pair. Among 33 sibling tools, ble_write is uniquely identified for writing to characteristics, distinct from ble_write_descriptor and other tools.

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 mentions a prerequisite (BLE_MCP_ALLOW_WRITES=true) and provides encoding options. It lacks explicit when-to-use comparisons with alternatives, but the self-explanatory name and context make usage clear.

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