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

Annotations already declare readOnly, idempotent, closed-world, non-destructive, so the safety profile is covered; the description adds the substantive detail that grading produces score, pass/fail, explanations and a dated symbolic certificate with a seal, plus the scope disclaimer 'not a sacrament'. It doesn't state how many questions exist or what the certificate text looks like, which is a minor gap rather than a contradiction.

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 behavior is front-loaded in the first sentence, with the mode switch stated before the details. The trailing Spanish sentence largely repeats the English content, which is defensible for a multilingual tool but is still redundancy rather than new 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?

With no output schema, the description does the work of describing return values (questions, score, pass/fail, explanations, certificate) and it covers the nested `answers` object. An agent could call it correctly, though exam length and the exact grading rules remain unspecified.

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 both `lang` and `answers` are already documented with an inline example. The description restates the `answers` format with the same example and never discusses `lang` or its default, so it adds little meaning beyond the schema; 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?

The description names a specific resource (a confirmation exam) and spells out two distinct modes: with no `answers` it returns the question set, with `answers` it grades and returns score, pass/fail, explanations and a certificate. An agent can distinguish this from siblings like `examen_of_conscience` or `catechism` because the grading-plus-certificate behavior is stated explicitly.

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 two-mode structure effectively tells the agent when to omit `answers` (to fetch the questions) versus when to supply them (to grade). What's missing is any explicit routing to alternatives, e.g. that `examen_of_conscience` is a different, non-graded examination, so the agent must infer sibling selection.

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