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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is covered; the description adds the substantive part — that the response carries policy and health state that gates later actions. It stops short of saying whether the data is cached or how fresh health is, which is the remaining gap.

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 sentences, front-loaded with the return content and followed by the usage trigger; nothing is padded. The trailing example is mildly redundant given the schema, which keeps it from a 5.

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 single-parameter read tool with an output schema and rich annotations, the description covers purpose, payload contents, and the decision it supports. An agent has everything needed to call it correctly without further inference.

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 100% and the schema already documents account_id, its length bounds, and its provenance from accounts_list. The description's inline example ({ "account_id": "acc_…" }) largely restates that format rather than adding new semantics, so this sits at the baseline.

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 names a specific verb and resource ('Returns one account') and enumerates what the payload contains: capabilities, sending policy (approval, caps, allowed recipients) and health. That clearly separates it from the list-style siblings, though it never names accounts_list or accounts_get_all_accounts_health as the alternatives, so differentiation is implied rather than stated.

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 gives an explicit trigger: 'Use it before acting on an account you are unsure of, e.g. to check whether sends need approval,' which tells the agent the decision this call de-risks. There is no when-not guidance or named alternative for bulk/health-only lookups, which keeps it below a 5.

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