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

Annotations already declare readOnly/idempotent/closed-world, so the bar is lower. The description still adds real behavioral context beyond them: the same call returns different content (real domain key vs. YOUR_API_KEY placeholder plus a register link) depending on whether setup_token is supplied — a non-obvious output variation with no output schema to document it.

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?

Two sentences, front-loaded with the primary action and the platform inventory, then the token-conditional behavior. Dense but every clause carries information; the platform list is slightly enumerative but justified since it defines scope.

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?

A read-only, idempotent tool with one required and three optional fully documented parameters and no output schema — the description covers the sole meaningful ambiguity (conditional output based on setup_token). Nothing essential to correct invocation is missing.

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 baseline is 3, but the description genuinely extends semantics by explaining the concrete effect of setup_token (real key vs. placeholder + register link) and by listing what the platform enum values produce. It adds meaning the schema fields do not carry.

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 ("Step-by-step install instructions") and enumerates the exact platform outputs (HTML snippet, WordPress/WooCommerce plugin, PrestaShop, GTM, Shoper). This is clearly distinguishable from siblings like analyze_site and verify_installation without opening the 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?

Usage context is implied rather than stated: the setup_token clause signals this should be called after create_account, and the schema notes platform usually comes from analyze_site's recommendedInstallMethod. But the description itself never says when to call this versus verify_installation or analyze_site, and gives no exclusions.

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