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

Annotations already establish readOnly, idempotent, non-destructive, non-open-world behavior, so the safety profile is covered. The description adds genuinely new behavioral facts: results are counts only, privacy-safe, and never expose a name. It does not describe pagination or how the limit interacts with the returned rows, but for a read-only aggregation tool this is solid supplementary context.

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 fact and the filter are front-loaded, which is good, but the opening sentence is an overloaded run-on with a nested parenthetical, and the 'so a person can see they would not be alone where they live' framing plus the trailing example questions largely restate the same idea. Tightening would lose no information.

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?

An output schema exists, so return shape need not be explained, and annotations carry the safety profile. What remains thin is the unspecified 'limit' parameter and the absence of any routing hint toward sibling tools for adjacent needs, but an agent has enough to invoke this 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 50%: 'place' is documented in the schema as a city or country word, which the description echoes, while 'limit' has no description anywhere. The description compensates for the filter parameter but leaves the 1-50 result cap (default 12) semantically unexplained, so it neither adds much beyond the schema nor fills the coverage gap.

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 concrete resource and scope: privacy-safe counts of believers by city and country, city-level, counts only, never a name. That is far more than a restatement of the name. It does not, however, explicitly contrast itself with plausible siblings such as find_churches_near or needs_near, so differentiation is left implicit.

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 example questions ('are there believers on Living Bread in Nairobi', 'how many are in Brazil', 'where is the family') make the intended use case concrete and easy to match against a user request. There is no explicit when-not guidance or pointer to an alternative tool for the related 'find people/churches near me' need.

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