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

With no annotations, the description carries the burden, and it does disclose return content (categories plus their searcher terms). However, it never states that this is a read-only, side-effect-free lookup, nor anything about caching or size, so the safety profile is left to inference from the zero-parameter schema.

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 sentences, no filler, and the resource definition is front-loaded ahead of the usage cue. 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?

No output schema exists, so the description must characterize the return value, which it does (categories with matching searcher terms). It is complete enough to call correctly, though it gives no sense of result shape or cardinality.

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 the schema cannot express argument semantics and the baseline of 4 applies. The description adds nothing further about parameters, but there is nothing to add.

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 a specific resource — the service categories navigi.ca uses, paired with the searcher terms each answers — so an agent knows this returns a controlled vocabulary, not services. It stops short of an explicit verb and never contrasts itself with siblings like find_services or services_near, so differentiation is only implicit.

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?

'Call this first when unsure which need word to use' gives a clear triggering condition and even an ordering hint (before searching). It does not name the alternative tools it should precede or say what to do once the term is known, so it is context without full routing.

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