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

Annotations already cover read-only, idempotent, non-destructive and closed-world, so the bar is lower; the description still adds real value by describing the rendered card, the pick interaction, and how a pick surfaces differently in ChatGPT ('Let's work on …' prefill) versus Claude (player opens, project name arrives in the next message). What it omits is scale/limits (how many projects the card can hold, whether there is paging) — a moderate gap for a listing tool.

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 is front-loaded in the first clause and every sentence carries content the agent needs (ordering, card contents, result summary, pick side-effects). The final sentence is long and packs two client-specific behaviours together, which slightly hurts scanability.

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?

With no output schema, the description correctly compensates by stating what the result contains (a count and the six newest projects with edit times) and what a pick produces. The main missing piece is the relationship to list_projects, which is essential context in a suite containing both.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. No parameter claims conflict with the empty schema.

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?

Uses a specific verb and resource ('Lists the person's Cardboard projects'), plus concrete scope: most-recently-edited first, with thumbnail, duration and last-edited time. An agent knows what it returns. However it never acknowledges the sibling list_projects, so the reader cannot tell why two listing tools exist.

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?

Usage is only implied: the card lets the person 'search the list there and pick a project,' which suggests this is the interactive/presentational listing path, versus list_projects presumably being the programmatic one. There is no explicit when-to-use/when-not statement and no named alternative.

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