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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds that each item carries its failure error and that failed documents are actionable via retry or replacement, which is real context beyond annotations, but it says nothing about result volume, ordering, or pagination for what could be a long failure list.

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?

A single tight sentence with the resource condition front-loaded and the motivation trailing. It is efficiently sized, though the noun-phrase fragment lacks an explicit verb, which costs a little clarity at the start.

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 no-required-parameter read tool with full schema coverage, rich annotations, and no output schema, the description covers what the tool returns and why it exists. Remaining gaps (pagination, ordering, whether the error is a message or a code) are minor for a tool of this complexity.

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?

There is only one optional parameter and schema description coverage is 100%, with the schema itself explaining that omitting app_id defaults to the owner's own Business Brain. The description adds no additional scoping semantics, so the baseline of 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 subset ('documents whose processing failed') and adds what is returned ('with the error'), which distinguishes it from the broad sibling list_knowledge_documents and from retry_knowledge_document. It stops short of an explicit verb ('list'), relying on the name and title to carry that, so it is clear but not fully self-contained.

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 clause 'so they can be retried or replaced' implies the downstream workflow and gestures at the retry/replace path, which is useful routing information. However, it never explicitly names retry_knowledge_document or add_knowledge_document as the follow-up, and gives no condition for choosing between retry and replace.

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