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

No annotations are provided, so the description carries the behavioral burden and does disclose the key mutation semantics: one default per post type, it replaces the previous default, and 0 clears it. It also explains the 404 special-case body rule. It does not cover auth/permission needs or what happens to posts currently relying on a replaced default, so it falls short of fully compensating for missing annotations.

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?

Purpose and scope are front-loaded, and the sibling distinction is compact and useful. The trailing 404-body sentence and the skill-doc rule add value but make the text dense; wording like "its body: a contentSource rule with context 404" is cryptic and could be tighter.

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 described. The description covers scope, mutation/replacement behavior, the 404 special case, and the alternative tool, which is sufficient for an agent to call this 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%, so the baseline is 3, but the description adds meaning beyond the schema: it clarifies that postType "404" maps to the frame of every not-found address and details that body's rules (contentSource with context "404", else notFoundPage). It reinforces the one-per-type and 0-clears semantics for templateId.

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 (make default) and resource (template as the DEFAULT frame for one post type), and explicitly distinguishes itself from assign-template-pages. An agent can tell what this does and where it sits relative to siblings without opening either 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 names the alternative (assign-template-pages) and the condition that selects it (per-page exceptions vs. whole-site default), and adds a required precondition (read the template-contract skill doc before the first call). Nothing about when to use this vs. alternatives is left to inference.

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