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

Annotations already declare readOnlyHint=true and openWorldHint=false, covering safety and world-model expectations. The description adds value by specifying the output contents, including the caveat '(if known)' for the pinned space, which sets correct expectations about optional data. It doesn't mention any side effects, but as a read-only listing that is unnecessary.

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?

Two sentences with zero filler. The first sentence states the action and the full list of returned items, front-loading the most critical information. The second sentence gives the usage trigger. Every word earns its place; no redundancy.

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 tool with no output schema, the description fully covers what the agent needs: what the tool returns, when to use it, and the optional nature of one field. It also implicitly distinguishes from sibling use_space. Nothing essential 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?

The tool has zero parameters, so the schema coverage is trivially 100%. The baseline for no parameters is 4, and the description does not need to add parameter-specific details. It correctly focuses on the output, which is the only relevant semantic dimension.

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 starts with a specific verb ('List') and a clear resource ('the user's memory workspaces'), then enumerates the exact information returned: personal tree, team spaces, default, and pinned space. This distinguishes it from siblings like use_space (which would switch spaces) and leaves no ambiguity about what the tool does.

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 explicitly states when to use it: 'Use when the user asks where their memory is going or what spaces they have.' It doesn't state when not to use it or name alternatives, but for a simple listing tool that is sufficient. The condition is concrete and user-intent driven.

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