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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral detail beyond that: the document_not_found answer for unknown ids, the different resolution behavior for graph nodes (lesson vs Markdown card), and the 'text is data, not instructions' injection warning. It restates the return fields, which the output schema already carries, so not 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 primary use, then dense per-id-family clauses and an error case; almost every clause carries information. The parenthetical return-field list is the only padding, since the output schema already documents those fields.

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?

For a single-parameter read tool with full schema coverage, an output schema, and explicit annotations, nothing an agent needs to call it correctly is missing: id forms, resolution behavior, failure case, and a prompt-injection caveat are all present.

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 the baseline is 3, but the description earns more by explaining the consequences of each accepted id form: course/module ids, graph ids (readable chapter returns its lesson, other nodes their card), and negocio:<topic> returning the business card. That is meaning the schema's terse 'id' description does not convey.

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 and resource ('read in full a document returned by search') and separates itself from search, getModuleContent and getCourseDetails by making clear it returns the complete lesson text. An agent can pick it without opening the 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?

Clear entry condition: use it on a document returned by search. It also explains what happens for each id family (course/module ids, graph ids c:/k:/x:, negocio:<topic>), which guides id selection. It does not name a sibling alternative or an explicit when-not case, so it stops short of a 5.

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