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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description adds a genuinely useful caveat beyond them: internal exempt workspaces may differ from the public tariff, so returned values may not match published pricing. It stops short of saying whether the read is authenticated per-workspace or what happens for workspaces with no exemption.

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?

Two short sentences, front-loaded with the action, and no filler. The second sentence earns its place by flagging the exemption discrepancy.

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?

A no-param, no-output-schema read tool still leaves the agent guessing what the returned 'policy' contains (rates, exemptions, currency, thresholds) and how to interpret it. The safety profile is well covered by annotations, but the content of the return value is not hinted at anywhere.

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 there is nothing for the description to disambiguate; baseline 4 applies. The description correctly signals the tool takes no scoping input, implying the workspace is resolved from the session context.

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?

Verb is clear ('Read') but the resource is stated as 'the actual workspace policy', which never says billing or pricing directly — the agent must infer it from the tool name and the word 'tariff'. The clarifying clause about internal exempt workspaces is helpful context, but the core purpose statement is vaguer than it should be.

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 is only implied: fetch this when you need the workspace-specific policy rather than published tariffs. There is no explicit instruction on when to prefer this over nearby tools like get_wallet, check_entitlements, or list_tts_rates, and no prerequisites or exclusions are stated.

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