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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral context by stating 'Returns live data — not cached from session start', which is not captured in the annotations, giving the agent insight into data freshness.

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?

The description is exactly two sentences, front-loaded with the action and resource. The first sentence states purpose, the second gives usage triggers and a key behavioral trait. No wasted words.

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 zero-parameter, read-only account status tool with comprehensive annotations, the description fully covers purpose, usage, and live-data behavior. No output schema is needed since the description enumerates the key return categories, and the tool's simplicity means nothing essential 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?

The tool has zero parameters, so the baseline is 4. The description compensates by listing what information the tool returns (balance, plan, graphs, profile), which helps the agent understand the output even without an output 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 starts with a specific verb 'Check' and names the resource 'current user's account status', listing concrete elements: API call balance, plan, enabled/disabled graphs, and profile info. This clearly distinguishes it from sibling tools that focus on graph data like list_graphs or search_graph.

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?

The description provides explicit when-to-use scenarios with example user questions ('how many API calls do I have?', 'what plan am I on?', 'what graphs can I access?'). It lacks explicit exclusions or alternative tool references, but the context is clear enough for a zero-parameter account-specific tool.

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