get_global_variable_value_at_address

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 discloses that the tool is for reading (not writing) and mentions the compile-time address requirement, which adds useful context. However, it lacks details on permissions, error handling, or performance implications, leaving behavioral gaps for a tool with no annotation coverage.

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 and front-loaded: two sentences with zero waste. The first sentence states the purpose, and the second provides usage guidance, both earning their place without redundancy or fluff.

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 is an output schema (which handles return values) and 100% schema coverage for the single parameter, the description is reasonably complete. It covers purpose and usage guidelines but could improve by addressing sibling differentiation or more behavioral details, though the output schema reduces the need for return value explanation.

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?

The schema description coverage is 100%, so the schema already documents the 'address' parameter. The description adds no additional parameter semantics beyond what the schema provides, such as format examples or constraints. This meets the baseline for high schema coverage but does not enhance understanding.

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 by its address (if known at compile-time)'. It specifies the verb ('Read'), resource ('global variable's value'), and method ('by its address'), but does not explicitly differentiate from its sibling 'get_global_variable_value_by_name', which reads by name instead of address.

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 clear usage guidance: 'Prefer this function over the `data_read_*` functions.' This indicates when to use this tool versus alternatives, specifically naming the 'data_read_*' functions as less preferred. However, it does not mention when to use this tool versus 'get_global_variable_value_by_name' or other siblings, which is a minor gap.

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