listCards

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

With no annotations at all, the description must carry the full behavioral burden; it does disclose the return contents (slugs and names) and the fixed count of 78, which is genuinely useful. It omits ordering, response shape (array vs object), and whether all 78 are always returned for every locale, which are the remaining traits an agent would want.

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 short sentences, no filler, with the scope and count front-loaded before the follow-up instruction. 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 trivial one-optional-parameter read tool with no output schema, the definition covers purpose, scale, and next step. A brief note on the returned structure or locale fallback behavior would close the last gap.

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 0% for the single optional parameter, so the description is the only place locale semantics appear, and it says only "in the requested language" without naming the parameter or explaining the five enum codes. The schema's enum and default of "en" do most of the work, so the description adds marginal but real meaning about what locale affects (the names).

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?

"List all 78 card slugs and names in the requested language" gives a specific verb (list), resource (card slugs and names), and even the exact cardinality, which tells an agent the full catalog size up front. It partially differentiates from siblings by pointing to getCardMeaning as the follow-up, though it says nothing about drawCards.

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?

The only guidance is the chaining hint "Use a returned slug with getCardMeaning," which implies this is a discovery/enumeration step. There is no explicit statement of when to prefer this over drawCards (e.g., browsing the catalog vs. drawing a spread), so the when-not case 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.