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

With no annotations, the description carries the full burden of behavioral disclosure. It clearly states 'Pure function, no network state,' which implies determinism and no side effects, and it adds the mutual-exclusion constraint. It does not describe error handling or return format, but for a pure function this is adequate and not misleading.

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?

Two tight sentences deliver the purpose, rationale, and mutual-exclusion rule with zero redundancy. The main verb and resource are front-loaded, and every phrase earns its place.

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?

The description covers what the tool does, its purity, and the essential invocation rule. The input schema fully documents both parameters, and no output schema exists, so return details are not required. A small gap is the absence of behavior when both or neither arguments are supplied, but 'exactly one' handles that implicitly.

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 baseline is 3. The description adds value by stating 'Exactly one of uri or task,' a crucial constraint not present in the schema, and by framing the difference between 'literal coordinate' and 'conceptual coordinate' even though the schema already describes those. This raises the score to 4.

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 states a specific action and resource: 'Compute a coordinate from a URI or a structured task descriptor.' It also explains the tool's reason for existing—centralizing normalization so agents don't diverge—which distinguishes it from the sibling tools (contradict, drop, reputation, sweep, watch) that appear unrelated in purpose.

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 gives clear context for when to use the tool: whenever a deterministic coordinate is needed, instead of agents implementing their own normalization. It also imposes the explicit rule 'Exactly one of uri or task.' However, it does not explicitly name sibling tools as alternatives or describe when not to use the tool, so it stops short of full exclusionary guidance.

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