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

Discloses a non-obvious behavioral trait beyond the annotations: rows are APPENDED, never deduplicated, so re-sending the same list stores it twice, with the remedy (delete first). Annotations only cover the safety profile (readOnly/destructive/openWorld), so this append semantics detail is genuinely additive.

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?

Front-loaded with the core action, then routing and the append caveat. Four sentences that mostly earn their place, though the compare_migration reference is slightly more verbose than needed.

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?

Complete for this tool: output schema exists so return values needn't be described, annotations cover the safety profile, and the description supplies the append/dedup caveat, sibling routing, and label grouping semantics.

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 75%, so the schema already documents siteUrlA/B, redirects, and label. The description reinforces A/B as source/target and explains label as the mechanism to keep migrations apart on one account, but adds no syntax or format detail 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 ('Saves redirect mappings (old URL -> new URL) for a site migration') and ties it to the source/target properties. It clearly distinguishes itself from siblings compare_migration (read) and delete_migration_redirects (clear).

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?

Explicitly routes the agent: use compare_migration for the before/after read, use these mappings to record old->new, and clear a set first with delete_migration_redirects when re-uploading. Both the when-to-use and the alternative are named.

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