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

Annotations already flag non-read-only, open-world, non-idempotent, and destructive. The description adds value beyond that by disclosing the fallback chain for scaffolding (template, then configured SEO/AEO starter, then bare repo) and the return value (site_id), which the agent cannot infer from the schema.

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?

Three front-loaded sentences with no filler: the action, the user-consultation rule, and the templating fallbacks plus return value. Every sentence carries distinct information.

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 create tool with no output schema, the description covers defaults, the privacy prompt, templating fallbacks, and the returned site_id, which is enough to call it correctly. It stops short of noting permission/auth prerequisites, but the openWorld annotation partly covers that.

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%, so the schema already documents name, private, and template. The description reinforces that template is owner/repo and that private/public should be confirmed with the user, but adds no syntax or format beyond the structured fields, matching the baseline 3.

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?

The description states a specific verb and resource ('Create a NEW GitHub repo as a code site') and clarifies the product's interpretation of a repo. It distinguishes this from the read-oriented siblings github_list_repos and github_link, though it does not explicitly differentiate itself from create_site.

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?

It gives concrete operational guidance: ask the user about private vs public first, and use a template repo optionally. It lacks an explicit when-not-to-use or naming of an alternative, but the conditional behavior (template → SEO/AEO starter → bare repo) gives clear context for invocation.

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