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

Annotations (idempotentHint=true, openWorldHint=true, readOnlyHint=false) already convey some traits, but the description goes well beyond them: it discloses the Bearer-token security model, the confirmation requirement, bounded expiry/use-limit behavior, and the explicit side-effect exclusion that no invitation is sent. This meaningfully constrains the openWorldHint rather than just repeating it.

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?

Three sentences, every one earning its place: core action with constraints, return value plus side-effect exclusion, and alternative routing. The key scoping info ('bounded', 'view or download', '30 days') is front-loaded before the return and routing details.

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?

Given the moderate complexity (6 params, a nested ShareInput, a confirmation flow, and an output schema), the description covers the essential decision points and return value without redundancy. It leaves two gaps: the purpose/provenance of expected_version, and how confirmation_token is obtained or required in practice — an agent may not realize a prior confirmation step exists beyond the 'After explicit confirmation' hint.

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?

With 0% schema description coverage, description must compensate, and it largely does: 'view or download' maps to permissions, 'expiring within 30 days' maps to expires_in_days, 'use limit' maps to max_uses, and 'after explicit confirmation' maps to confirmation_token. However, expected_version (a required 64-hex field) and idempotency_key semantics are left undocumented in both schema and description, creating a real gap for a required parameter.

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?

Description states a specific verb+resource ('create a bearer room link') with concrete bounds: view/download permissions, 30-day expiry, use limit. It also distinguishes from sibling tools like sparkroom.list_share_links and sparkroom.revoke_share_link by focusing on creation, and name alone already separates it from sparkroom.create (room vs. link).

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?

Provides an explicit precondition ('After explicit confirmation') and names the alternative with selection conditions ('Use SparkLaunch for password links or uploads'). The 'sends no invitation' clause further clarifies when this tool is inappropriate, giving an agent clear routing logic without inference.

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