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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds real behavior beyond that: 'no key needed' authentication, the payload contents (agent level 0-5, where the agent stopped and why, what it can and can't do, how it gets in and pays), and the 2.5-5 KB vs 13-35 KB size difference between modes. It stops short of latency or pagination details, but nothing essential is missing.

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?

It is a single dense sentence but front-loaded with the purpose and the alternative before the payload details. Every clause earns its place (purpose, input source, alternative, safety, size), though the parenthetical enumerations make it feel packed rather than streamlined.

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?

An output schema exists, so return values needn't be explained. The description still covers what is inside the result, the two size regimes, that no key is required, and which sibling handles the narrower surface question. That is complete enough for a two-parameter read tool; only operational details like latency are absent.

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%: the schema already documents that slug accepts a slug, name or domain, and that brief toggles between headline and full record with the same size ranges. The description mostly restates this, though mentioning 'its slug from search_tools' adds a small workflow hint about where the identifier comes from. Baseline 3 is appropriate given the schema does the heavy lifting.

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 and resource ('Get one product's result') with explicit scope ('when the question is whether an AI agent can use it'). It names the sibling it is not ('Use get_agent_surfaces instead when you only need its API, MCP, CLI and SDK'), so an agent can route between them without opening either 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 the exact condition that selects this tool (whether an agent can use a product) and the explicit alternative with its own condition (get_agent_surfaces for surface inventory only). It also points at the source of the key input ('its slug from search_tools'), removing an inference step.

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