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

Annotations already declare a safe, idempotent read, so the description is free to add the useful part: results come back as snippets with ids that must be resolved via get_writing. It says nothing about ranking, snippet length, or behavior under a very broad query, which is the remaining gap.

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?

Three short sentences: scope, when to use, and what comes back. Scope is front-loaded and every sentence carries distinct information with no restating of the title.

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 and the description still summarizes the return shape, so an agent knows it gets ids to follow up on. Only the relationship to the general `search` and `discussions_of` siblings is left unstated.

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%, so era, author, limit, and query are already documented in the schema (including the early/later split and example author names). The description adds no field-level meaning beyond what the schema states, so the baseline 3 applies.

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 verb (Search) and a precisely bounded resource (Christian writings outside the Bible: church fathers, councils/creeds, commentaries, later Catholic/Orthodox/Protestant/Jewish works). The explicit 'outside the Bible' boundary lets an agent distinguish it from search_scripture without opening either schema.

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?

Gives a concrete use condition ("when the user asks what early Christians, a theologian, or a tradition wrote about a subject") and hands off the follow-up step to get_writing. It does not address when to prefer the broader `search` or `discussions_of` siblings, so the routing is clear but not exhaustive.

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