device_update

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

Annotations only indicate that this is a non-read-only, non-destructive operation. The description adds genuinely useful behavioral detail: omitted fields retain their current values, and tags/variables maps are wholly replaced rather than merged. It does not clarify null-value behavior, but the core behavioral semantics are well disclosed.

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?

Two sentences, no filler. The first sentence states the core behavior, and the second adds the critical map-replacement caveat. It is appropriately sized for a tool with 10 parameters and is easy to parse.

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 that the input schema enumerates all parameters, an output schema exists, and annotations cover the safety profile, the description supplies the missing operational semantics: partial update and replace-vs-merge behavior. Minor gaps remain around null handling and under-explained parameters like skip_fcnt_check, but nothing blocks a competent agent from using it 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 description coverage is 0%, so the description carries the parameter-semantics burden. It explains the two non-obvious map parameters (tags and variables) and the general partial-update rule, but eight other parameters, including skip_fcnt_check and join_eui, rely entirely on their names for meaning.

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 uses a specific verb and resource ('Update ... a device') and clearly distinguishes this from sibling tools by scoping it to partial updates of existing devices. The phrase 'only the given fields' also disambiguates it from device_create and device_delete.

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 gives clear context for when to use the tool: to modify selected fields of an existing device while preserving others. It does not explicitly name device_create/device_get/device_delete as alternatives or provide when-not-to-use exclusions, so it stops short of a 5.

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