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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds non-obvious behavior beyond the annotations: the sign-in gating and the interactive sign-in prompt, which an agent must anticipate before invoking.

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, the core action front-loaded before the auth caveat, with no wasted clauses. The sign-in consequence sentence is slightly wordy but carries genuine behavioral information.

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 no-param, read-only list tool with an output schema already defining the return shape, the description covers purpose and the one operational caveat (auth). Nothing essential is missing, though it does not describe result size or pagination.

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 no parameters, so the baseline is 4. The description's field enumeration describes output rather than input and does not conflict with the empty schema.

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 ('List the spaces of the signed-in Velven account') and enumerates the returned fields (slug, title, status, hosting, page). It is immediately distinguishable from the sibling verbs publish, rollback, search_docs, and versions.

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 states the precondition ('Needs sign-in') and the consequence of calling without it (the app prompts the person to sign in). It does not name alternative tools or when not to use this one, but for a zero-parameter account-scoped list tool the guidance given is sufficient.

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