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

With no annotations, the description carries the burden of behavioral disclosure. It clearly states the role enum and the owner-only permission, which adds useful context. However, it does not disclose what happens on conflict (e.g., does update replace role?), error conditions, or the effect of the operation beyond the action itself.

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?

The description is extremely concise with two short sentences, and every word contributes value. It front-loads the action and role constraint. However, it is arguably too terse for a tool with three parameters and no schema descriptions, though the brevity itself is a positive trait.

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?

The tool has no annotations, no output schema, and 0% schema description coverage, so the description needs to be more complete. It provides the role constraint but does not explain how a space is identified by slug, what 'member_email' refers to, what happens on update, or any error/return behavior. This is insufficient for a mutation operation with multiple parameters.

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?

Schema description coverage is 0%, so the description must compensate. It explains the 'role' parameter with allowed values, but does not explain 'slug' or 'member_email' beyond their property names. The token 'member_email' is self-explanatory, but 'slug' is ambiguous without context. Description covers only one of three parameters.

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 uses a specific verb 'Add/update' with a clear resource 'space member', and the role values are explicitly listed. It is easily distinguished from sibling tools like brainkb_add_space_graph or brainkb_assign_role.

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?

The description provides a critical usage constraint ('Owner only') but does not explicitly state when to use this tool over alternatives such as brainkb_assign_role. No when-not-to-use guidance is given, so usage context is partially implied rather than fully documented.

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