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

Annotations already declare destructiveHint=true and openWorldHint=true, and the description adds genuinely non-redundant context: this is a total replacement, so the caller must supply the complete intended array. It still omits what happens to existing rules not included, whether the change is atomic/staged, and whether prior state is recoverable.

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, no filler, with the danger warning front-loaded immediately after the operation description. Every clause carries information.

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 and annotations carry the safety profile, so the description needn't explain return values. But for a destructive full-ruleset replacement, the description should at minimum point to the read tool as a prerequisite and clarify the interaction with phase-specific replace siblings; that omission materially affects correct invocation.

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 71%, so the schema documents zone, rules, context_id, account_slug, and environment_slug. The description adds nothing parameter-specific beyond the 'full intended rules array' hint for `rules`, and leaves `phase` (the enum that actually selects the target ruleset) entirely unexplained.

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 with scope ('Replace entrypoint rules for a phase'), which cleanly separates it from cf_ruleset_entrypoint_get and cf_rulesets_list. It does not, however, distinguish it from cf_account_ruleset_entrypoint_get or the phase-specific replacers (cf_waf_custom_rules_replace, cf_transform_rules_replace), and the 'entrypoint' vs 'account ruleset entrypoint' distinction is left implicit.

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?

'Use with care: send full intended rules array' implies the replace semantics but gives no explicit when-to-use or when-not-to-use guidance. Nothing tells the agent that the phase enum value http_request_firewall_custom overlaps with the sibling cf_waf_custom_rules_replace, nor that reading current rules first via cf_ruleset_entrypoint_get is the recommended precondition.

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