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

Annotations already declare destructiveHint=true and idempotentHint=false, so the safety profile is known. The description adds governance context (MCP approval requirements set by the org admin; business workflow approvals always apply), which is genuinely beyond the annotations, but it never explains the key destructive behavior — whether the `permissions` payload replaces or merges with existing role permissions.

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?

Only two sentences and the purpose is front-loaded, so it is not bloated. However the second sentence is dense jargon ('MCP approval requirements', 'business workflow approvals') whose relevance to invoking this update is ambiguous enough that it does not fully earn 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?

An output schema exists so return values need no explanation, but for a destructive, non-idempotent mutation with zero schema documentation and a nested permissions field, the description omits the two things an agent most needs: which fields are server-owned, and replace-vs-merge semantics for permissions.

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% and the nested `data` object (name, color, isDefault, description, permissions) is entirely undocumented. The description only asserts that server-owned fields are excluded without saying which fields those are, and adds nothing about how the free-form `permissions` value is interpreted.

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 ('Configure/edit custom_role'), which separates it from create_custom_role, delete_custom_role and get_custom_role by implication. It does not explicitly name the sibling alternatives or the id-based targeting, so it stops 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 create_custom_role or update_custom_field, and no prerequisites such as 'fetch the role with get_custom_role first' or admin permission requirements. The only constraint offered ('server-owned fields are excluded') is a limitation, not a usage routing rule.

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