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

Annotations flag destructiveHint=true and openWorldHint=true, but the description goes further by specifying exactly what is destroyed (files omitted from the payload are removed) and what is preserved (the URL). That is precisely the context an annotation cannot convey, and there is no contradiction.

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 filler, with the replacement semantics front-loaded before the file-completeness rule. Every clause earns its place.

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 three-parameter mutation tool with full schema descriptions, full annotations, and an output schema, the description supplies the one non-obvious behavioral fact (full replacement) plus the sibling relationship, leaving nothing an agent needs to call it correctly.

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 the nested file schema already documents path, content, encoding, the 100-file/10 MB limits, and that index.html is the home page. The description's emphasis on the complete file set reinforces schema semantics but adds no new per-parameter detail, so 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?

Names a specific verb ('Replace the files') and resource (a site published with publish_site), and states the effect on identity ('it keeps its url'). An agent can distinguish it from publish_site and create_upload_link 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?

Explicitly ties this tool to sites created via publish_site and gives the critical operating rule that every file must be sent because omissions are removed. It does not state when to prefer siblings like create_upload_link or what preconditions exist, so it stops short of full when/when-not coverage.

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