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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=false, so the safety profile is covered; the description adds value with "takes effect immediately" (live, instant effect on the blog) and the duplicate-avoidance warning. It stops short of saying what happens if a redirect already exists for the same path, which is the key ambiguity for a destructive, non-idempotent operation.

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 short sentences, all front-loaded: what it does, when to use it, parameter formats, then the duplicate check. No sentence is redundant and nothing is buried.

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?

For a 2-parameter, no-output-schema tool with annotations covering the safety profile, this covers purpose, prerequisites and parameter shape well. The only gap is not stating the overwrite/conflict behavior when a redirect from the same path already exists.

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% and both property descriptions are already clear, so the schema carries the load. The description's "from is a path on this blog, to is a full HTTP or HTTPS URL" largely restates what the schema says, adding little constraint information beyond it — the baseline 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?

Specific verb + resource (create a permanent 301 redirect) with the meaningful qualifier that it takes effect immediately. It implicitly separates itself from update_redirect/delete_redirect by using the create verb, but never names those siblings to make the boundary explicit.

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?

"Only when requested" is a genuine when-to-use restriction that prevents proactive redirect creation, and "List existing redirects first to avoid duplicates" names a concrete sibling (list_redirects) as a prerequisite step. No explicit when-not-to-use case or comparison against update_redirect is given, so it stops short of full routing guidance.

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