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

Annotations declare readOnlyHint=false and destructiveHint=false, but the description adds crucial context beyond them: ingestion runs in the background and returns a runId, embedding spends workspace inference credit, the call may return `needs_confirmation`, and there are size/count limits. This is rich behavioral disclosure that goes well beyond the structured safety hints.

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 description is front-loaded with the core purpose, then flows into operational details (background ingestion, limits, alternatives, approval gate) in a compact, information-dense manner. Every sentence contributes actionable guidance without redundancy or filler.

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 mutation tool with no output schema, the description covers everything an agent needs: ingestion behavior, return value (runId), follow-up tools, limits, approval flow, and duplicate-avoidance. Annotations cover safety, and the description fills all remaining gaps, making the definition self-sufficient.

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 schema already documents kbId, sources, encoding, mimeType, and workspace/approvalId. The description restates the encoding and mimeType rules (utf8 for text, base64 for PDF/docx) and limits (50 sources, ~10 MB each), which are already in the schema constraints. It adds little new semantic meaning beyond what the schema provides, so baseline 3 is appropriate.

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 ('Adds documents') and resource ('knowledge base'), and immediately clarifies that ingestion starts. It names sibling tools (workbench_kb_ingestion_status, workbench_kb_search, workbench_kb_documents_list) so an agent can distinguish this tool from alternatives without opening schemas.

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?

Explicitly tells the agent to check workbench_kb_documents_list first to avoid duplicates, to use workbench_kb_ingestion_status only when the user asks (not poll), and that search works only after ingestion finishes. It also identifies ideal source material (<attached-file> blocks) and notes the approval gate, giving clear when/when-not guidance.

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