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

Annotations already declare a non-read-only, open-world, non-idempotent write; the description adds substantive lifecycle behavior on top: an id and ownership token are issued, nothing becomes public before verification, and pending entries expire after 14 days. It also notes per-itch-path identity ('Each itch game path is a separate identity'), implying repeat registrations create distinct records. It does not address what happens on a duplicate submission or how the token is scoped, leaving a modest gap for a non-idempotent mutation.

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?

Five tight sentences, front-loaded with what the tool does, then input expectations, then the return value and verification lifecycle. Every sentence carries information; only the leading 'List' framing is wasted/confusing wording.

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 10-parameter open-world mutation with no output schema, the description covers the essentials: expected inputs, that an id plus ownership token come back, the required verify_app follow-up, and the 14-day expiry of unverified entries. Missing are duplicate-handling behavior and per-field meaning for the remaining parameters, but the critical call-and-follow-up picture is complete.

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?

At 40% schema coverage the description does real work for `url` (domain you control, exact itch game page, omit only for store-only apps) and frames the optional `token`. However, it says nothing about `name`, `description`, `category`, `platforms`, `appStoreUrl`, `playStoreUrl`, or `webBuildUrl` semantics beyond what the schema already carries, so half the surface stays undocumented in prose.

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 names the concrete resource (the Appside public app catalog) and the exact follow-up action: get an id and ownership token, then call verify_app, which cleanly separates it from the verify_app sibling. The opening verb 'List' is a slight mismatch for what is plainly a registration/mutation tool, but the surrounding sentences ('Returns an id and ownership token', 'Nothing is public until verified') remove any real ambiguity.

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 states prerequisites explicitly ('No Appside store or account required'), the input expectation (plain-text metadata plus your website or exact itch.io page, or a store listing for store-only apps), and the next step (publish the token then call verify_app). It stops short of enumerating when NOT to use it versus siblings like submit_index_entry or claim_mcp_listing, but the context it does give is clear.

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