Android Scalability Architecture Guide

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is fully covered elsewhere. The description adds nothing behavioral: it doesn't say whether content is cached, how 'refresh' affects session state beyond the schema note, or how large/responsive the responses are.

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 compact sentence, front-loaded with the highest-value keywords and no filler. It is appropriately sized for a lookup tool, though the fragmentary keyword-list style means it carries less information per token than a declarative sentence would.

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 should clarify what comes back (explanatory guidance, snippets, references) and how to scope a query; it only enumerates topics. For a zero-required-parameter retrieval tool this is minimally adequate but leaves the agent guessing about response shape and granularity.

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 description coverage is 100%, so baseline is 3. The topic list in the description does echo and expand the schema's example values ('Paging3', 'offline-first', 'cold start', 'modularization', 'recomposition'), giving the agent a rough taxonomy of valid topics, but adds no syntax, normalization, or fallback behavior beyond the schema.

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 is a bare topic list ('Paging 3 + RemoteMediator, offline-first sync, HTTP caching, cold start, modularization, Compose recomposition performance') with no verb stating what the tool actually does — retrieve guidance, generate code, or explain trade-offs. It does usefully differentiate from siblings by domain coverage (scalability/performance vs. android_navigation3_guide or material3_expressive), but the agent must infer the operation from the name and title.

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?

No when-to-use guidance at all: nothing says when this beats architecture_reference, kotlin_best_practices, or android_official_search for the same subject matter. The only usage cue is the schema-level note that omitting 'topic' returns an index, which is not restated or contextualized in the description.

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