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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explicitly states 'Read-only' (non-destructive) and notes the result is 'Small enough to read in full', implying no pagination or truncation. These are useful behavioral traits beyond the bare action, though it does not mention rate limits or auth—acceptable for a simple read-only list.

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?

The description is two concise sentences. The first front-loads the action, resource, and returned fields; the second adds read-only status and usage guidance. Every word earns its place, with no redundancy or filler.

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?

Despite no output schema, the description enumerates all returned fields and asserts the list is complete and small enough to read in full, so an agent knows what to expect. It also gives usage context. It doesn't mention pagination or limits, but given the explicit 'small enough' claim, the coverage is adequate for this simple tool.

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 has zero parameters, so the input schema is empty. Per the calibration, a tool with 0 parameters gets a baseline of 4, and there is nothing for the description to add about parameter meaning. The description correctly focuses on output and usage instead.

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 ('List') and a precise resource ('every app in the Spark catalogue') and enumerates the exact fields returned (id, name, tagline, description, tags, homepage, links). It differentiates from siblings by explicitly contrasting with search_apps, making its scope unambiguous.

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 description gives an explicit when-to-use directive: 'prefer this over search when the question is about the range of apps rather than a specific one.' This tells the agent the condition for selecting this tool over a named alternative (search_apps), and by implication when not to use it (for a specific app, which would be get_app).

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