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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, and the description largely restates them ('read-only... does not change settings or documents'). It adds one genuinely new fact — the returned set is limited to 'accessible' Spaces — but says nothing about ordering, format, or limits.

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, no filler, with the primary use case front-loaded and the read-only caveat second. Every clause earns its place.

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 parameterless read-only lookup with no output schema, the description covers purpose, trigger, and the key behavioral fact (accessible Spaces). Slightly incomplete in that it does not hint at what each Space entry contains, but nothing needed to call 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 no parameter semantics to convey; baseline is 4. The description does not introduce phantom parameters, which is correct.

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 (list/look up) and resource (documentation Spaces), and distinguishes itself from siblings like list-space-documents by scoping to Spaces themselves. An agent can tell this apart from the many 'list-space-*' tools without opening a 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?

Explicit trigger: 'when the user asks to see, choose, or look up their documentation Spaces,' plus a sequencing hint about needing a numeric space_id first. No when-not guidance or named alternative, but the context is clear enough to route correctly.

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