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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint, so safety is covered. The description adds genuine context beyond them: it reveals the tool's role in the auth/workflow chain and that the returned id feeds workspaceId on Sightglass calls, plus the plan values it returns. It stops short of describing response shape/pagination, but no output schema means that gap is minor.

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?

Front-loaded with the resource and its return content, with usage details following. Every clause carries workflow value; it is slightly dense but nothing is wasted or padded.

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 read-only, zero-parameter list tool with no output schema, the description supplies what's needed: what is returned (workspaces + plan tiers), when to call it, and how the result is consumed downstream. Nothing an agent needs to invoke it correctly 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 takes zero parameters, so there is nothing for the description to disambiguate; the baseline for a 0-param tool is 4. The mention of the workspaceId it produces is useful downstream context, not a parameter gloss.

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 ('the user's Replo workspaces') and adds what each entry carries ('each one's plan (free, starter or pro)'). An agent can distinguish this from the sibling list_* tools immediately.

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 prescribes when to call: right after sign-in, and when the user wants to switch workspaces. It also gives the decision procedure (use the only workspace, or ask once when several exist) and how to use the result (pass id as workspaceId on Sightglass calls).

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