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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description usefully reasserts that nothing is selected or charged, but says nothing about result ordering, pagination, or how the canonical inventory changes between calls.

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?

One sentence, tightly front-loaded with the verb and scope, with zero filler. Every clause (canonical inventory, search facets, no-selection caveat) 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?

With no output schema and 0% schema description coverage, the description should do more: it never conveys the shape of results (list of services with prices and capabilities?) or how 'limit' caps them. Adequate for routing, incomplete for correct invocation.

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 0%, so the description must carry the parameter burden. It maps its facets onto query, capability, protocol, and maxPrice ('maximum advertised price'), which is real added value, but leaves the 'limit' parameter unexplained and gives no syntax or combination semantics for the free-text query.

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 (Search) and resource (complete canonical PHION inventory), plus the facets that can be searched: task, capability, protocol, price. The phrase 'without selecting or charging' implicitly separates it from action-oriented siblings like phion_execute or phion_preflight, though no sibling is named.

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?

'Without selecting or charging' implies this is a pre-selection, discovery-only step, which hints at when to use it. However, it never names the alternative (e.g. phion_get_service for a known service, phion_execute to act) or states explicit exclusions, leaving the agent to infer.

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