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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds context the annotations cannot: it is a point-in-time snapshot, and a cross-workspace call returns 404, which tells the agent how failure manifests. It does not mention auth scoping or consistency lag, but the essentials 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?

Purpose leads, the field enumeration follows, then the use case, then the error behavior last. The list of five minute pools is long but each name carries information an agent would otherwise have to guess. No filler sentences, though the enumeration is dense enough to slow scanning slightly.

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?

An output schema exists, so return structure need not be explained, and the description still names the salient fields an agent would care about. For a single-parameter read tool with full annotation coverage, nothing needed to invoke it correctly or interpret success/failure 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?

One required parameter at 100% schema description coverage, so the schema already explains workspaceId and the api-key match constraint. The description adds only the indirect cross-workspace 404 behavior, which is consistent with the schema but not additional parameter-level meaning. Baseline 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?

States a specific verb and resource ('Get the current usage and entitlement snapshot for your workspace') and enumerates exactly what the snapshot contains: subscription tier, five free-minute pools, purchased packs, period consumption, LLM-enrichment tokens. An agent can distinguish this from getWorkspaceUsageThisPeriod and getUsageBySource without opening either schema.

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?

Gives an explicit decision context: 'Use this to check whether you have enough capacity before kicking off an expensive job.' That is real when-to-use guidance rather than an implied purpose. It stops short of naming the sibling period/source tools as alternatives for historical or per-source breakdowns.

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