Get ACS variable

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

No annotations are present, so the description must carry the behavioral disclosure burden. It says 'Read' which implies a non-mutating operation, but it does not disclose the return type, error behavior for invalid indices, or the role of the 'instance' parameter. This is minimal and adds little beyond the tool name.

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 (10 words) with no filler. It is front-loaded and directly states the action and resource, earning every word.

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 three parameters, no output schema, and no annotations, this description is under-specified. It does not explain what is returned, invalid-index behavior, or how 'instance' affects the operation, leaving significant gaps for an agent.

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 mentions 'world or global' (mirroring the enum) and 'by index' (the parameter name), but it doesn't explain what index refers to, the difference between world and global, or the meaning of 'instance.' The description adds no semantic value beyond what the schema already provides.

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 states the tool reads an ACS variable specifically by scope ('world or global') and index. This distinguishes it from siblings like set_acs_var (write), list_acs_vars (list all), and find_acs_symbol (search).

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 verb 'Read' implies when to use it, but there are no explicit exclusions or alternative tool recommendations. It doesn't say 'use set_acs_var to modify' or 'use list_acs_vars to enumerate variables.'

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