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

Annotations only declare the mutation/safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=false), so the description's added context is genuinely valuable: required permissions per scope, the Viewer read-only caveat, MANAGER+ default for org libraries, and the guarantee that agent-created libraries are user-visible and never the system auto-stash variant.

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 action, then constraints, then permissions, then the visibility caveat — a sensible order with no filler. Slight deduction because the 'name is 1..200 chars' clause duplicates the schema's own description text, and the sentences are dense and multi-clause.

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 5-param mutation tool with no output schema, the description covers scope selection, validation bounds, authorization requirements, and the visibility semantics of the created object. Nothing an agent needs in order to call it correctly is missing.

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 coverage is only 40% (projectId, proposalId, and description are undocumented), but the description compensates fully: it names all three scope selectors, explains the 'exactly one' exclusivity rule, and restates the name length bound plus the optional description. An agent can construct a valid call from the description alone.

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?

Opens with a specific verb+resource ('Create a document library') and immediately enumerates the three mutually exclusive scoping modes, which cleanly separates it from create_project, create_proposal, and upload_library_document. It never explicitly names a sibling it is not, so differentiation is implicit rather than stated.

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 states the calling constraint ('Specify exactly one scope: projectId, proposalId, or scope="org"') and gives the per-scope permission prerequisites, so an agent knows the correct invocation shape. It stops short of when-not-to-use guidance or pointing at alternatives such as upload_library_document for existing libraries.

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