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

With no annotations, the description carries the burden and does disclose a real behavioral trait: the output shape varies by engine capability (prose vs. raw type list). It doesn't state that the operation is read-only/non-mutating, or anything about cost/size of the result, which would matter for a no-annotation 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?

Two short sentences, both load-bearing: one defines the output, one gives the prerequisite ordering. The usage hint is front-loaded at the end where it is most likely to be read as an instruction.

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 single-optional-parameter introspection tool with no output schema, the description covers return contents, format variability, and call ordering — enough to invoke correctly. The remaining gap is sibling disambiguation, which is the one thing an agent still has to infer.

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 coverage is 100% on the single optional 'asTypes' parameter, so the schema already documents it. The prose ('In prose when the engine can write it, else as a list of types') adds a little semantic context about the default path but largely restates the schema description — baseline 3 is appropriate.

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 gives a specific verb+resource ('Describe the database') and enumerates the returned contents (collections, properties, types, descriptions), so the agent knows exactly what it gets. It doesn't explicitly distinguish itself from 'ask' or 'query' by name, though the 'before writing a query' clause gestures at the distinction.

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 an explicit precondition: 'Call this before writing a query', which is genuinely actionable sequencing guidance. It stops short of naming alternatives or exclusions (e.g., when to use 'ask' instead of this for exploratory questions).

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