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

Annotations already declare readOnly, idempotent, non-destructive, and open-world, so the safety profile is covered. The description adds genuinely new behavioral context: the framing 'never a ranking, never an argument' tells the agent the output is neutral/charitable, and it sketches what comes back (family tree, sourced page, links). It does not mention limits or error behavior, keeping it from a 5.

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?

Front-loaded with the core purpose in the first clause, then supporting detail and example queries. The theological flourish ('one Body, many rooms, Christ the head of all') is somewhat decorative, but the 'never a ranking, never an argument' clause earns its place as behavioral guidance. Mostly efficient, minor padding.

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-value documentation is not required, and the annotations cover the safety profile. Given the tool's modest complexity (two string inputs), the description plus structured fields are sufficient for correct invocation. Missing only a single-tradition alternative pointer to be fully complete.

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 description coverage is 100% — both 'a' and 'b' have clear descriptions with examples in the schema itself. The description's examples ('Catholic vs Orthodox') merely echo the schema's examples and add no new parameter semantics. Baseline 3 is appropriate when 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?

States a specific action (comparing two Christian traditions side by side) and what is produced: family tree, sourced page, links, and posture. It is distinguishable from siblings like heritage_lookup because it explicitly handles two inputs compared against each other. It stops short of a 5 only because the core 'compare' verb is implied by the name rather than stated plainly.

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?

Concrete trigger questions ('what is the difference between Baptists and Methodists', 'Catholic vs Orthodox') tell the agent exactly when to reach for this tool. However, it names no alternative sibling (e.g., when to prefer heritage_lookup for a single tradition) and gives no exclusions, so it lacks the 5-level when-not guidance.

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