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

Annotations cover safety and idempotency, and the description adds genuinely new behavior: every X read is billed at X's prices, neither feature actually syncs yet, and enabling inbox can fail with a scope-list error requiring reconnect. That is exactly the context a caller needs before flipping a flag.

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 short sentences, no filler. The action and scope come first, then billing rationale, then the permission/error caveat.

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 non-destructive, idempotent toggle with no output schema, the description covers defaults, cost, permission prerequisites, and error semantics. Only the update-object nesting is left entirely to the schema.

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 67% and the schema already documents profileId and accountId, while the description only clarifies what the inbox/analytics booleans mean semantically. It adds meaning for the capability flags but says nothing about the nested update wrapper structure.

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 (turn on/off) and resource (X account's paid background reads, named as analytics and inbox), and it is clearly distinguishable from read-side siblings like get_x_usage.

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?

Explains the default state (both off) and the cost-driven reason to leave them off, which effectively tells the agent when enabling is warranted. It does not name an alternative tool for viewing usage, but the context is otherwise explicit.

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