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

Annotations already declare readOnlyHint=true and destructiveHint=false, so 'Read only' repeats structured data rather than adding it. However, the description does add substantive behavioral context: the result is verbatim from portaur.com and never includes prices, which sets expectations for output content. It says nothing about result size, ordering, or whether the list can change over time.

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?

Three short sentences, front-loaded with what it returns and followed by the read-only and no-prices constraints. No filler or restated title language beyond the useful scope statement.

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 zero-parameter read tool with no output schema, the description must carry the return shape, and it does (name, summary, description, verbatim from the site). Minor gap: no indication of how many services come back or whether the response is paginated, so an agent can't anticipate payload size.

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 to disambiguate; baseline 4 applies. The description correctly implies a full unfiltered listing rather than a search.

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?

States a specific verb (lists) and resource (Portaur services) and specifies exactly what each item contains: name, plain-language summary, fuller description. That detail distinguishes it from siblings like about_portaur or pricing_approach without opening a schema.

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?

Explicitly excludes a plausible wrong use case — 'It never returns prices' — and names the correct alternative, pricing_approach. It lacks an explicit 'use this when the user asks about what Portaur offers' clause, but the routing guidance against the nearest sibling is clear.

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