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

Annotations declare readOnlyHint=false, destructiveHint=false, openWorldHint=true, but the description adds substantial context beyond them: the plan is immutable and requires explicit customer approval, an empty set clears associations, competitor validation may read fresh Amazon Catalog relationships, and changed relationships require a new plan with no silent cached fallback. These are real behavioral traits an agent needs.

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?

Front-loaded with the core action and scope, then the exclusions. Mostly every sentence earns its place, though the 'Does not apply tracking changes' point is partially redundant with the workflow note in the schema description.

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?

With rich annotations, an output schema, and a fully described nested input schema, the description covers everything else needed: immutability, approval requirement, clearing semantics, fresh-validation caveats, and the follow-on execution step. Nothing material 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?

Schema description coverage is 100% and the nested fields already document critical semantics — competitorAsins is a 'Complete replacement set, not an append,' empty array clears, PARENT vs CHILD ASIN rules, max 10. The description's 'Replaces the full associated competitor set' and 'An empty set clears associations' merely echo what the schema already states, so baseline 3 applies.

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?

States a specific verb and resource — 'Prepares and persists an immutable keyword-rank tracking change plan' — and scopes it precisely to replacing 'the full associated competitor set of one existing owned-product tracker.' This clearly separates it from apply_keyword_rank_competitor_replacement (execution) and prepare_keyword_rank_tracking_changes (keyword changes).

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?

Explicitly states what it does NOT do — 'Does not create independent competitor tracking or change keyword status. Does not apply tracking changes' — and the schema description lays out the prepare → review → approve → confirm → execute workflow and says to query capabilities and quotas first. It stops short of naming the specific alternative siblings (e.g., prepare_keyword_rank_tracking_changes) for other change types.

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