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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: it discloses the selective result shape and the fallback behavior when no rules exist ('returns an outline and the steps to draft them'), which an agent cannot infer from annotations.

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, front-loaded with the return value and its scope. The second sentence is a long run-on that could be tightened, but every clause (which rules are included, the empty-state behavior) 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?

No output schema exists, so the description carries the burden of explaining returns, and it does: it enumerates the four kinds of content returned and covers the no-rules case. Combined with annotations covering safety, an agent has what it needs, though it never states that all parameters are optional or what happens with partial input.

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%, so all three parameters are already documented, including the dependency of parts/screen on projectId. The description restates the same project/screen/parts scoping without adding format or edge-case detail beyond what the schema provides, so the baseline of 3 applies.

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 gives a specific verb and resource ('Returns the Markdown rules the user's Better Design team wrote') and clarifies the scope (project guidelines, part rules, brand-wide bans, screen specs). It is distinguishable from set-team-rules/propose-team-rule by verb, though it never explicitly names a sibling like get-review-rules, so it falls short of full sibling differentiation.

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?

It implies the usage context (when building a screen, given project/screen/parts) and even describes the empty-state path, but gives no explicit when-to-use vs. when-not, no prerequisites, and no routing against the many related rule/design-system siblings. Usage is inferred rather than stated.

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