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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorldHint=false, so safety is covered. The description adds useful behavioral context by disclosing the information returned (pricing, licence, features) and that it is sourced, which the annotations do not convey. It stops short of saying what happens for unknown tools or how sources are cited.

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 the trigger condition and immediately followed by the return content. The trailing example largely duplicates the schema's example text, so the last sentence earns little of its space.

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?

The tool is simple (one array parameter, no output schema, low-risk read), and the description covers the trigger, the data returned and a usage example. Only marginal gaps remain: the 4-tool ceiling lives solely in the schema and unknown-slug behavior is unstated.

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% and the schema already documents slug format with examples plus the 2-4 item bounds. The inline example in the description repeats the schema's own example, adding no new semantics such as slug resolution behavior or error handling for unrecognized tools.

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 verb (compare) and resource (AI coding tools/app builders/agents) and states what the output contains: sourced pricing, licence and features side by side. It is clearly distinguishable from find_tool_for_task or get_tool by virtue of the side-by-side comparison framing, though no sibling is named explicitly.

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?

"Use when the user asks to compare AI coding tools, app builders or agents ('X vs Y')" gives a concrete trigger condition. There is no when-not guidance and no explicit pointer to alternatives like recommend_stack or find_tool_for_task for non-comparison lookups.

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