Change Thing State

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

With no annotations, the description carries the burden. It clearly states the mutation action and the two modes but does not disclose behavior when both parameters are provided, potential side effects, or error conditions. The output schema exists, which may cover response structure, but the description omits edge-case behavior.

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 extremely concise yet informative—two sentences front-load the core action and immediately explain the two operational modes. Every word earns its place, with no redundant or tangential content.

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 the presence of an output schema, 100% parameter documentation, and a simple operation, the description adequately covers the essential behavior. It explains the two ways to modify state, meeting the needs for typical use. Minor gaps like interactions when both parameters are set are not covered but are not critical for this simple tool.

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 100%, so the schema already defines each parameter fully. The description merely rephrases the same information (set_value = new direct value, op = signed integer to add). It adds no new meaning beyond what the schema provides, meriting the baseline score for high coverage.

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 specifies the action (change state) and the two distinct methods (direct set via set_value or incremental via op). It distinguishes this from sibling tools like get_thing_state (read) and update_thing (broader updates) by focusing solely on state modification.

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 explains the two parameter usage patterns ('set directly' or 'add a signed integer') but does not explicitly guide when to choose this tool over alternatives such as update_thing. It implies use for state-only changes but lacks explicit exclusions or alternative suggestions.

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