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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds a meaningful non-schema behavioral constraint (never guess a source; ask the user), which prevents a whole class of bad calls, though it says nothing about ordering conflicts or error behavior on a bad URL.

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, zero padding: purpose first, then the critical constraint. Nothing repeats the schema or annotations.

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 6-parameter mutation tool with no output schema, the description covers purpose and the key input-integrity rule, and the schema carries full parameter detail. It stops short of noting anything about the result of insertion or failure handling, but nothing essential for correct invocation is missing.

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%, including the after/parentId/position interplay and provider semantics, so the baseline is 3. The description's provider examples ('youtube for videos, google-maps for maps, iframe for third-party embeds') largely restate the enum descriptions already in the schema, adding little beyond it.

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 ('Insert') plus resource ('embedded content') and enumerated subtypes (YouTube video, Google Maps location, iframe embed). An agent can distinguish this from sibling inserters like editor_insertImage or editor_insertDocumentsBlock without opening the schema.

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?

Gives a strong operative rule — use a real user-provided source URL and ask the user rather than fabricating one. That is clear when-to-use guidance for the main failure mode, though it names no alternative sibling tools (e.g. editor_insertImage) for adjacent cases.

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