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

Annotations already declare idempotentHint=true, destructiveHint=false, and openWorldHint=false, so safety and repeatability are covered. The description adds nothing beyond restating a mutation: it doesn't say whether this is a partial merge (unspecified fields preserved) or a full replace (unspecified fields cleared), nor whether authorization as the listing owner is required. That ambiguity is the single most consequential behavior for a nested-object update tool.

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?

A single front-loaded sentence with no filler or repetition. It is efficient, though the brevity borders on under-specification for a mutation of a seven-field nested object.

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?

Given a mutation tool with a nested input object, no output schema, and only 33% schema description coverage, the definition is thin but not empty: annotations carry the safety profile and the schema documents individual fields. The critical missing piece is whether omitted fields are preserved or reset, which an agent needs before calling.

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 33% across three top-level parameters, with the nested input object carrying its own per-field descriptions. The description roughly maps to those nested fields (name, description, prices, source) but omits the id parameter and says nothing about how folder/source_url/repository_id interact as alternative source specifications. It adds marginal meaning over the schema but does not compensate for the coverage gap.

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 ("Changes") and resource ("a plan") and enumerates the mutable facets: name, description, prices, source. That distinguishes it from create_plan and remove_plan by implication. It stops short of stating scope or constraints, so it is clear but not maximally differentiated.

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?

There is no guidance on when to call this versus create_plan or remove_plan, no prerequisites such as owning the plan or being its author, and no preconditions like the plan existing. Usage must be inferred entirely from the verb.

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