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

Annotations already declare destructiveHint=true and openWorldHint=true, so the mutation profile is covered structurally. The description adds one genuinely useful behavioral detail — that omitting script disables route script binding — but does not warn that creating a route immediately re-routes live zone traffic, nor mention the account_slug requirement when the zone is uncataloged.

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 compact sentences with the action first and the required parameter highlighted. The second sentence is somewhat telegraphic ('optional to disable route script binding') and could be phrased more cleanly, but there is no filler.

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 not be explained, and annotations cover the destructive profile. However, for a mutation that changes live traffic routing on a zone, the description omits operational context (account_slug fallback rules, effect on existing routes) that an agent would need before calling it.

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 coverage is 100%, so the baseline is 3. The description clarifies the semantic consequence of omitting script (disabling the binding) rather than just restating 'Worker script name', which is a modest value-add, but it says nothing about zone, account_slug or context_id beyond the schema.

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 ('Create a Workers Route'), which is clearly distinguishable from the cf_workers_route_update and cf_workers_route_delete siblings. It doesn't explicitly name those siblings, but the create verb plus the adjacent toolset makes the distinction obvious.

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 updating an existing route, nor any prerequisites such as needing a deployed script or a specific zone/account setup. The only usage-like statement is that pattern is required, which duplicates the schema's required list.

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