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

Annotations only flag readOnlyHint=false, openWorldHint=true and idempotentHint=false; the description goes well beyond them by disclosing quota metering against the link owner's monthly limit, the credential types accepted, and a prompt-injection contract for handling the answer as untrusted data in <document_answer> tags. That is exactly the kind of context annotations cannot carry.

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?

Content is segmented into purpose, metering, safety, auth and args blocks with zero filler sentences; each paragraph carries load-bearing information. It is a little long for two parameters, but the security and credential paragraphs justify their length.

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 an output schema present the description needn't explain return values, and it still usefully describes how to treat the returned answer. Purpose, auth options, quota behavior, parameter conditionalities and safety handling are all covered, so an agent has everything needed to invoke it 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 description coverage is 0%, so the description carries the full burden and does so: 'question: max 4000 chars' and moat_link as the bare hash (not a full URL), optional for mds_/share-derived mdo_ credentials and required for mdp_/account tokens. This conditional-requirement detail is richer than any schema structure conveys.

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 first sentence gives a specific verb+resource: 'Ask a question, get an AI-synthesized answer from a shared file.' That is unambiguous and distinct from sibling tools like extract_fields or get_link. It never names an alternative explicitly, so sibling differentiation is implied rather than stated, keeping it at a 4.

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?

It establishes the clear context of use (questioning a document uploaded by the link owner) and supplies the credential-dependent conditions for supplying moat_link, which tells an agent whether it can call the tool with its current auth. It gives no when-not-to-use guidance and does not point to extract_fields for structured extraction, so it falls 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.