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

No annotations are provided, so the description carries the full burden. It does not state that this is a read-only lookup, does not mention required permissions or the agent_id ownership scope, and does not hint at the shape of the result. It reads as a data description rather than a behavioral contract.

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 with the scope front-loaded; nothing is redundant. The second sentence earns its place as a purpose statement, though it is slightly promotional.

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 tool with no annotations, no output schema, and an undocumented parameter, the description should disclose at least read-only semantics and the grouping grain of the response. It leaves the agent guessing about return structure and access requirements.

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 description coverage is 0% for the single required parameter agent_id, and the description only implies 'one agent' without clarifying ID vs name format, where to obtain it, or whether it must belong to the caller's workspace. It adds marginal meaning over the bare 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?

The description states a specific verb+resource: per-channel credit spend for a single agent, with concrete examples of channels (widget, telegram, phone). This clearly distinguishes it from a generic credit-usage tool, though it never names the closely related siblings get_credit_usage_for_agent or get_credit_usage_by_agent that an agent must choose between.

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?

It implies a use case ('Identifies the costliest channels') but gives no explicit when-to-use or when-not-to-use guidance. With four other credit-usage siblings in the list, the absence of any routing rule is a real gap.

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