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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely non-obvious behavior: web and mobile share different reference sets and the platform parameter changes which docs are returned. It omits return format/volume details, but for a read-only lookup this is solid.

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?

Front-loaded with purpose, then the topic catalog, then the critical warning about reading docs first, then the platform caveat. The guide list is long but each entry is load-bearing for topic selection; no filler sentences.

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, the description still characterizes returns ('index lists every guide and widget', widget type returns full syntax). Both parameters and the required one are covered, and the web/mobile distinction closes the main ambiguity for calling it correctly.

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%, so the baseline is 3, but the description adds real semantics beyond the schema: it enumerates the valid topic classes ('index', guide names such as 'app'/'view'/'actions', and widget type names) and explains the effect of platform='mobile'. That goes past the terse schema strings.

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+resource ('Read Fieldproxy's app-building reference') and immediately enumerates what each topic value yields, so an agent knows exactly what retrieval this performs. It is clearly distinct from sibling doc tools like get_automation_docs or describe_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?

Gives strong prescriptive guidance ('Read the relevant doc before writing any app or screen JSON') plus the platform-selection condition ('pass platform mobile for a mobile app'). It does not explicitly contrast itself against the sibling get_automation_docs, which is the one remaining routing gap.

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