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

Annotations already declare readOnlyHint, idempotentHint, and closed-world behavior, so the safety profile is covered. The description adds non-obvious domain context: the linked=false/rule=null empty result shape and the crucial warning that rules are 'advisory conventions, not machine-enforced'. That is meaningful behavior beyond annotations, though it doesn't discuss permissions or tenancy edge cases beyond what schema covers.

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?

Four tight sentences, front-loaded with the core action, then parameter guidance, then the empty-result case, then the alternative. No sentence is redundant or bloated.

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?

With an output schema present, the description needn't enumerate return fields, and it appropriately highlights only the salient linked=false/rule=null case. Combined with the advisory-rules note and the sibling routing, an agent has what it needs; only minor multi-tenant nuance lives solely in the schema.

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 100% and every parameter is documented there, including the tenant_slug fallback and the owner_slug requirement. The description's 'Pass scope=tenant|project|group; for project/group also pass owner_slug' repeats the schema rather than adding new semantics. Baseline 3 is appropriate when the schema does all the work.

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?

Uses a specific verb+resource ('Fetch the rule document linked to one scope') and explicitly contrasts with the sibling kb_rules_list_for_context. An agent can distinguish the single-scope lookup from the context-wide listing without opening either 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?

States the exact alternative (kb_rules_list_for_context) and the condition that selects it ('when you want every rule that applies to an authoring context at once'). It also gives per-scope parameter guidance ('for project/group also pass owner_slug'), leaving nothing ambiguous about when to call this tool.

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