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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered without the description. The description adds a genuinely useful behavioral fact not present in the structured fields: a 15-credit cost per call, which lets the agent budget calls. It stops short of 5 because auth requirements and failure/error behavior for invalid IDs are unstated.

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 short lines, zero filler, with the core purpose front-loaded and the cost note clearly separated. It is efficient, though the extreme brevity leaves no room for the parameter detail the tool actually needs.

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 simple read-only lookup with annotations covering the safety profile and no output schema to explain, listing the returned fields plus cost makes it largely complete. The gaps are the undocumented space_id format and lack of any error/precondition note, which are meaningful for a keyed single-resource fetch.

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?

One required parameter with 0% schema description coverage — the schema gives only the title 'Space Id' and no format. The description does nothing to compensate: it never says whether space_id is a numeric ID, a slug, or a full URL, which is the single most likely source of invocation error.

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 ('Return a Space's details') and enumerates the fields returned (title, host, speakers, state, listener counts), which tells the agent exactly what it gets. No sibling covers Spaces, so differentiation is effectively implicit rather than stated, which keeps it just short of a 5.

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?

No guidance on when to use this versus other tools, no prerequisites (e.g. must the Space be live?), and no note about what happens for expired or invalid Space IDs. The only usage-relevant statement is the per-call cost, which is a constraint rather than an invocation guideline.

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