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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is clear. The description adds only the scoping notion of 'current' and 'by id', but does not disclose error behavior, permissions, or data freshness. With annotations covering the main concerns, a 3 is appropriate.

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 a single, compact sentence with no filler. Every word ('Return', 'one', 'current', 'plan', 'by id') contributes meaning, and the key operation is front-loaded.

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 single-parameter read tool with readOnly and idempotent annotations plus an output schema, the description is mostly complete. The only gap is navigation: an agent without a planId may not know to use list_offers, but that is a minor omission given the tool's simplicity.

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 0%, so the description must compensate. 'by id' maps directly to the required planId parameter and gives it meaning, but it does not explain what a valid planId looks like or how to obtain one. The parameter name is self-explanatory, so this is minimally adequate.

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 uses a specific verb ('Return') and a specific resource ('one current plan') with an identifier qualifier ('by id'). This clearly distinguishes it from siblings like dp_commercial_list_offers (plural) and dp_commercial_compare_offers, which operate on multiple plans.

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 implies usage: you need a specific plan id to fetch a single plan, which differentiates it from listing or comparing offers. However, it does not explicitly state when to prefer this tool over siblings or mention alternatives like list_offers when an id is not available.

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