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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows it's a safe, read-only operation. The description adds useful behavioral details beyond annotations: the plan limit (2 without Pro, 5 with Pro) and that 'one share_url opens them all together.' It does not contradict the annotations and provides extra context about the result sharing.

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 three short sentences with the main action front-loaded. It includes the limit and the comparison use case, and the share_url behavior is added as a third point. There is no fluff, and every sentence earns its place. It is appropriately concise for the tool's complexity.

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?

The tool is complex with nested objects and many settings, but the description only gives a high-level overview: run multiple plans, rank them, and share via URL. It does not mention the output structure (e.g., what fields are returned in the summary) or the error handling for Pro-only settings, which the schema hints at. While the schema covers parameter details, the absence of an output schema means the description should clarify what the agent can expect in return; it only mentions ranking by final value and share_url. This is adequate but not complete for a tool of this complexity.

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 description provides no parameter-specific information; it does not mention as_of, include, settings, or any of the plan fields. Schema description coverage is only 50%, meaning half of the parameters lack descriptions in the schema, and the description does not compensate for this gap. For example, as_of has a pattern but no description, and the agent would need to infer its meaning from the pattern alone. The description should have helped clarify parameter roles but does not.

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 ('Run'), a resource ('up to 5 plans'), and the outcome ('rank them by final value'). It distinguishes itself from the sibling run_dca by focusing on multiple plans, and it names common comparison dimensions ('assets, cadences or start dates'). This is a clear, specific statement of purpose.

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 gives clear context for when to use this tool: when you want to compare multiple plans side by side. It also notes the Pro account limit (2 vs 5 plans), which helps set expectations. However, it does not explicitly mention the alternative for a single plan (run_dca), nor does it state when NOT to use it, so the guidance is implicit rather than explicit.

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