Set ACS variable

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. It only says 'Write,' which implies a mutation, but does not disclose side effects, scope persistence, or error behavior for invalid indices. No mention of the optional instance parameter or its effect on game state.

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 a single concise sentence with no excess wording. It effectively communicates the core action in minimal space.

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 tool with 4 parameters, no annotations, and no output schema, this description is too thin. It lacks crucial context such as instance semantics, side effects on game state, prerequisites (e.g., running game), and relationship to get_acs_var/list_acs_vars.

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 must compensate. It explains 'world or global' (scope) and 'by index' (index), but omits the 'instance' parameter entirely and does not clarify the meaning of 'value' beyond the obvious. This is insufficient for a 4-parameter tool with no schema descriptions.

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 'Write' and identifies the resource as 'an ACS world or global variable by index.' This clearly distinguishes it from sibling tools like get_acs_var (read) and list_acs_vars (list).

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 no guidance on when to use this tool versus alternatives, no prerequisites, and no mention of when not to use it. It simply states the action without context.

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