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

Annotations already declare readOnlyHint, openWorldHint=false, idempotent, and non-destructive, so the safety profile is covered. The description adds real value by specifying the output convention (degrees from true north) and that a distance is returned alongside the bearing. However, it does not disclose failure behavior, such as an unresolvable city name or the absence of geocoding outside the open-world boundary.

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 dense sentence with the core information front-loaded: quantity, inputs, unit, and a bonus output. The nested parenthetical clarifying the Kaaba in Mecca is defensible for a broad audience but is the only mild clutter. Nothing extraneous.

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?

With no output schema, the description correctly explains what is returned (bearing plus distance), which is the right call for a simple read-only computation. The gap is that all three parameters are optional, so the definition should say what happens when no input is provided or when place and coordinates are both given. That omission leaves a realistic invocation path undefined.

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 100%, so the schema already documents place, latitude, and longitude, including formats and range limits. The description reinforces the either/or semantics between place and coordinates but adds no format, default, or precedence rule beyond that. Baseline 3 applies where the schema does the heavy lifting.

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 names a specific computed quantity (Qibla bearing toward the Kaaba), its inputs (city or coordinates), its unit (degrees from true north), and an extra return value (distance). This distinguishes it clearly from the sibling tools, which deal with calendars and prayer times rather than a bearing computation. It stops just short of 5 because the verb is only implied by the noun phrase rather than stated outright.

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?

Usage is only implied: 'from a city or coordinates' tells the agent the two input modes exist but not which to prefer or when. There is no mention of alternatives, no guidance on ambiguous place names, and no statement about what happens if neither mode is supplied.

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