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

Annotations indicate readOnlyHint=true, signaling a safe read operation. The description adds behavioral context: it searches within an adjustable radius and returns every matching Mass and Confession at each church. No contradictions, and the description enriches the annotation with search scope and result detail, though it omits sort order or pagination.

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 two concise sentences. The first sentence states the core purpose, and the second adds essential usage details (location format, required day and time window, radius). No redundant or fluff content.

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 5 parameters, no output schema, and no siblings, the description covers all necessary context: tool purpose, valid inputs (location, day, time window), and optional radius. It is self-contained for an agent to use correctly.

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 all parameters. The description adds minimal value beyond the schema: it clarifies that location should be a place name, not coordinates, and that radiusKm defaults to 2km. This slight enhancement does not significantly compensate beyond baseline 3.

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 finds Catholic Mass and Confession times within a day and time window at churches near a place in NYC. It specifies the resource (Mass and Confession), location scope (NYC), and time constraints. No siblings exist, so differentiation is not needed.

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 context: it requires a place name (not coordinates), a day of the week, and a time window. It gives examples of valid locations. However, it does not explicitly state when not to use the tool or mention alternatives, which is acceptable given no siblings.

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