trmnl_mirror_device

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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false and openWorldHint=true, so 'changes remote state or starts work' adds little. The genuinely useful addition is the sharable-visibility precondition, but the description is silent on the key behavioral question of whether mirroring is a one-time copy or a persistent relationship, and whether the target device's existing playlist is replaced. 'Run only within the user-authorized scope' is generic boilerplate.

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-loaded and compact: purpose in the first line, mechanism second, prerequisite third. The trailing sentence about remote state and authorization scope is boilerplate that partly duplicates the annotations and could be cut.

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 three-parameter mutation with no output schema and nested body/path objects, the description supplies what an agent needs to call it correctly: the direction of the copy, the master identifier's meaning and the sharable precondition. Persistence semantics are the only notable gap and are partly signaled by the sibling stop/resync tools.

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 only 33%, so the description must compensate. It does clarify the direction of the copy (master's playlist onto 'this device', i.e. the path device_id) and the meaning of master_friendly_id, but never mentions the 'profile' parameter and does not state that device_id is the target.

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 states a concrete verb and resource: pointing one device at another device's shared playlist, and explains that the master's sharable playlist is copied onto this device. It is clear enough to act on without opening the schema, but it never distinguishes itself from close siblings such as trmnl_copy_device_playlist, trmnl_resync_device_mirror or trmnl_stop_mirroring_device.

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?

A real prerequisite is given: the master must have visibility set to sharable. Beyond that, there is no guidance on when to mirror versus copy a playlist or resync/stop an existing mirror, and no exclusions, so the agent must infer the choice from tool names alone.

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