get_global_variable_value_by_name

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

No annotations are provided, so the description carries the full burden. It mentions the compile-time condition ('if known at compile-time'), which is useful behavioral context. However, it doesn't disclose other important traits like whether this is a read-only operation, what happens if the variable doesn't exist, error conditions, or performance characteristics. The description adds some value but leaves significant gaps.

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 with just two sentences. The first sentence states the purpose, and the second provides usage guidance. Every sentence earns its place with no wasted words, making it front-loaded and efficient.

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 there's an output schema (which handles return values), 1 parameter with 100% schema coverage, and no annotations, the description provides adequate context. It covers the core purpose and gives important usage guidance about preferring this over data_read functions. However, for a tool that reads values with compile-time constraints, more behavioral transparency would be beneficial.

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 documents the single parameter 'variable_name' with its description. The description doesn't add any parameter-specific information beyond what's in the schema. According to the rules, when schema coverage is high (>80%), the baseline is 3 even with no param info in the description.

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's purpose: 'Read a global variable's value (if known at compile-time)'. It specifies the verb ('Read') and resource ('global variable's value'), making the function clear. However, it doesn't explicitly differentiate from sibling tools like 'get_global_variable_value_at_address' or 'data_read_*' functions beyond a general preference statement.

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 explicit guidance: 'Prefer this function over the `data_read_*` functions.' This gives clear context about when to choose this tool over alternatives. However, it doesn't specify when NOT to use it (e.g., for runtime values) or mention other alternatives like 'get_global_variable_value_at_address'.

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