pair

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

With no annotations provided, the description carries the full burden of behavioral disclosure, and it does meaningfully: it states the prerequisite state, discloses both code modes, and reveals that pairing requires an interactive user confirmation on the phone. It falls short of a 5 by not addressing blocking/timeout behavior or what the tool returns (particularly the auto-generated code).

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?

Three sentences with zero waste: action, prerequisite, then the two-path flow logic folded elegantly into one sentence. The main verb+object is front-loaded, and every sentence earns its place.

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?

For a 2-parameter tool with no annotations and no output schema, the description covers the prerequisites and both operational paths well. The main gap is that it never states how the agent obtains the auto-generated code to relay to the user (presumably via the tool response), which is an important post-invocation detail given there is no output schema.

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 100%, so the baseline is 3 — the schema already documents both parameters. The description reinforces the code parameter's decision rule ('if a code was generated on the device, pass it; otherwise one is generated'), which adds marginal value, but it contributes nothing new for the device parameter beyond what the schema states.

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 opens with a specific verb+resource: 'Initiate pairing with a discovered Android device.' This clearly distinguishes it from its siblings — unpair is the reverse operation, list_devices/get_device are read-only, and call/batch/screenshot/screen_stream are operations that presuppose pairing.

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 clear context for when the tool applies: the device must already be discovered and running the FreeCode Agent app, which implies the list_devices step precedes this. It also explains the two invocation flows (pass an existing code vs. auto-generate). However, it never explicitly names alternatives or exclusions, such as pointing to unpair as the reverse operation.

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