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

The annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description adds real migration behavior beyond them: old bundles become named field sets with exact columns, the five test bundles are removed, and the tool stops working on a stated timeline. The GDPR/PECR sentences add some output-scope context (corporate subscribers only by default) but read largely as legal boilerplate rather than call guidance.

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 deprecation warning and replacement are correctly front-loaded, which is the right structure. However, the final two sentences about lawful basis and PECR subscriber defaults are long, tangential to invoking a deprecated list tool, and dilute the actionable content.

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?

Return values are covered by the output schema and the deprecation path is fully explained, so the core is complete. The gap is that the input schema accepts arbitrary additional properties yet the description only defers argument mapping to an external URL, leaving no in-definition account of how a call should be shaped.

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?

With zero declared parameters the baseline applies, and the schema describes the argument object as 'the arguments of the old tool, unchanged during the deprecation window' with a pointer to the mapping doc. The description itself adds no per-argument meaning, but there is nothing to document.

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 first sentence names a specific verb and resource ('lists the field bundles an order can deliver') and immediately flags deprecation with a named successor ('Use list_field_sets instead'). An agent can distinguish this from list_field_sets and get_pack_details without opening any 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?

It states explicitly which sibling to use instead, gives the sunset condition (12 months after the new tools launch, after three emailed notices), and points to a migration doc. When-not-to-use and the alternative are both unambiguous.

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