Read this month's usage

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

Goes well beyond the annotations, which only cover read-only/idempotent safety. It discloses that going over never stops a redirect and that new_links_paused means create_link returns 402 until upgrade or month end - non-obvious consequences an agent could not infer. It stops short of stating rate-limit or caching behavior, but the important behavioral semantics are present.

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 'Read-only. This calendar month's usage (UTC)...' followed by enumerated return fields and their thresholds. Two sentences, no filler, every clause carries information.

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 no output schema and no parameters, the description must carry the return-value burden and does: field meanings, limit/null semantics, level thresholds, and the downstream effect on create_link. An agent has everything needed to call and interpret it.

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?

Zero parameters, so the schema imposes no burden and a baseline 4 applies. The description still clarifies return-field semantics (null = no limit, level thresholds at 80% and 100%), which compensates for the absent output schema.

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 and resource: reads this calendar month's usage against the workspace's plan. It enumerates the exact returned quantities (billed taps used/included, new links created/included, level, new_links_paused), which clearly separates it from analytics siblings like get_analytics and get_workspace.

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?

Usage context is implied - check this to know whether the workspace is near or over its plan limits, and why create_link might be answering 402. But no sibling is named and no explicit when-to-use / when-not-to-use rule is given.

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