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

No annotations are present, so the description carries the disclosure burden. It does add useful behavioral context by stating the output is a compass direction in degrees 0-360, but it omits edge-case behavior (e.g. identical coordinates) and says nothing about determinism, errors, or cost. Adequate but incomplete for a no-annotation tool.

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?

A single sentence with the core operation front-loaded. The redundant 'Bearing:' prefix echoes the tool name, but there is otherwise no waste.

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 simple stateless math tool with no output schema, the description covers inputs, operation, and output range well. Only edge-case behavior and coordinate-format expectations are missing.

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 coverage is nominally 100%, but the schema descriptions are placeholders ('Lat1 to process'). The description compensates by pairing the parameters into two coordinates (lat1/lon1 and lat2/lon2), which the schema alone does not make clear. It still omits coordinate format expectations (decimal degrees, valid ranges).

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?

Specifies a clear verb (calculate) and resource (initial bearing between two GPS coordinates), plus the output unit and range. It does not, however, distinguish itself from nearby siblings like x402-compass-direction or x402-geo-distance, which an agent could plausibly confuse it with.

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 no when-to-use guidance, no prerequisites, and no mention of alternatives such as distance or compass-direction tools. The agent must infer applicability entirely from the phrasing.

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