Update DCA Plan

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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the agent knows this is a mutating, potentially destructive operation. The description confirms it updates an existing plan and adds that it returns the updated plan. However, it does not clarify whether unspecified fields are preserved or reset (partial vs. full update), which is a meaningful behavioral gap. It does not contradict annotations.

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 two sentences, with the core purpose front-loaded and a concise list of editable fields. Every word earns its place, and there is no redundant or extraneous information. This is an efficiently structured definition.

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 description covers the tool's basic function and return value, and the schema explains every parameter. However, it omits important conditional dependencies: e.g., if frequency is set to Weekly, day_of_week is likely required, and similarly for Monthly/day_of_month. These cross-parameter constraints are neither in the description nor the schema descriptions, leaving an agent to infer them. The presence of an output schema is false, but 'Returns updated plan' suffices for return-value clarity.

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 100%, so all parameters are documented in the schema. The description repeats the allowed values for frequency, day_of_week, and day_of_month exactly as in the schema, providing no additional semantic value. It does not add constraints or clarify relationships between parameters, so the baseline score of 3 is appropriate.

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 opens with a specific verb and resource: 'Update an existing DCA plan by plan_id.' It then enumerates the mutable fields (amount, frequency, day_of_week, day_of_month), which clearly differentiates it from sibling DCA tools like dca_create, dca_pause, dca_resume, and dca_stop. An agent can discern this tool's role without opening the schema.

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 context is clear: use this when you need to modify an existing DCA plan, identified by plan_id. It does not explicitly state when not to use it or name alternatives, but the purpose and sibling names make the appropriate invocation obvious. Lacks explicit exclusions or conditional guidance, so not a 5.

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