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

Annotations already declare non-read-only, non-destructive, idempotent, closed-world behavior, and the description adds real context: the 12-month sunset, three emailed notices, and a migration link. However, the GDPR/PECR material describes audience composition rules rather than what this save call does, so some of it is context padding rather than operational disclosure. Meaningful but partly off-target beyond 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?

Deprecation and the replacement are front-loaded, which is exactly right. The closing legal-basis and PECR sentence is long and only loosely tied to invoking this tool, so it dilutes an otherwise tight 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?

For a zero-parameter deprecated tool with an output schema and full annotation coverage, everything an agent needs is present: deprecation status, replacement, migration path, and sunset timing. Return values need not be explained because an output schema exists.

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?

Zero parameters, so the baseline is 4, and the schema itself explains that legacy arguments are unchanged and mapped by the adapter. The description adds nothing about the parameter passthrough beyond pointing at the same migration doc.

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 ("saves the filters held in the server session under a name") and immediately labels itself "Deprecated" with the replacement named. An agent can distinguish it from save_audience without opening either 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?

Explicitly routes the agent to save_audience and explains why (organisation-shared audience definitions, saved lists carry over as aud_ IDs). It also gives the deprecation timeline and a migration mapping URL, so the when-not-to-use case is unambiguous.

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