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

Annotations already mark the tool as non-read-only and idempotent; the description adds meaningful behavior by specifying what is persisted (usage patterns, build preferences, simulator metrics, cached responses) and what is never persisted (source code, credentials, personal information). It also discloses automatic cache-location selection and auto-registration with the MCP server, adding context beyond the schema.

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 document is organized under headings and front-loads the core purpose, making it scannable. However, it repeats the privacy point and the automatic-location behavior across sections, and the Advantages list is largely promotional rather than necessary for invoking the tool.

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 tool with one optional parameter and no output schema, the description is operationally complete: it explains the results (activation confirmation, resolved cache directory, storage writability, privacy notice, next steps) and lists related tools. No critical invocation detail appears to be 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?

The input schema provides zero description coverage and only a bare 'cacheDir' string property. The description compensates fully: 'cacheDir (string): Custom directory for cache storage. If omitted, uses intelligent location selection.' This tells the agent the parameter is optional and what happens when it is absent.

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 opens by saying the tool 'Enable[s] opt-in persistent state management for learning across server restarts' and 'Activates file-based persistence' for XC-MCP's caching systems. It names a specific action on a specific resource, and the Related Tools section distinguishes it from persistence-disable and persistence-status.

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 frames the tool as the opt-in activation path for persistence and lists concrete contexts where it is beneficial: retaining learned configurations, accelerating repeated workflows, team collaboration, and CI/CD runs. It names related tools for disabling and checking status, but it does not explicitly say when not to use this tool or directly compare selection criteria.

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