Qibla direction

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so safety is covered. The description adds genuine value with the true-north vs magnetic-compass caveat and a preview of result fields, but it says nothing about output structure or precision limits beyond that caveat.

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 core definition and input modes are front-loaded in a single dense sentence with no filler. The trailing web-version URL is marginal but harmless; the sentence is long yet every clause carries payload.

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?

There is no output schema, so the description carries the return-value burden and discharges most of it by naming the bearing, distance, compass point and turn instruction. For a stateless read-only calculator this is largely sufficient, though the absence of an explicit success/error shape is a minor gap.

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 baseline is 3, but the description adds information the schema lacks: that city and coordinates are alternative inputs rather than cumulative ones, and that heading exists specifically to produce a turn instruction. That resolves an ambiguity the flat property list leaves open.

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?

States a precise verb+resource: computes the great-circle bearing and distance from true north to the Kaaba from coordinates or a named city, and enumerates the derived outputs (compass point, turn instruction, correction from a device heading). No sibling tool does anything similar, so it is instantly distinguishable.

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?

Makes the two input modes explicit ('any coordinates or a known city') and explains the optional heading as the trigger for the turn instruction, so an agent knows what to supply and what extra output it unlocks. It stops short of naming when not to use it or pointing at related tools like prayer_times.

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