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

Annotations already cover readOnly=false, openWorld=true, idempotent=true and destructive=false, so the bar is lower, yet the description adds real substance: it explains the idempotency mechanism (keyed on location, uri, placeActionType, so a duplicate returns the existing link) and flags that accepted action types are category-dependent. It stops short of describing auth/permission requirements.

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 tight sentences with the purpose front-loaded, followed by two behavioral caveats. No filler, and each sentence carries distinct information.

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?

For a create tool with no output schema, the description covers purpose, the idempotent-return behavior, and the category constraint. It could go slightly further on return payload or permission prerequisites, but nothing essential to calling it correctly 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 the baseline is 3, but the description adds meaning beyond the schema by explaining that place_action_type acceptance varies by category and by naming the (location, uri, placeActionType) key tuple that governs uniqueness. This clarifies behavior of two parameters that the schema alone only names.

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 ('Add an action button') and names the target ('a Google Business Profile location'), so the operation is unambiguous. It does not explicitly reference the sibling tools (place_action_link_delete/update/links_list), though the create verb implicitly separates it from them.

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 is implied by the create semantics — you call this to add a button — but there is no explicit 'use this when' or routing to the update/delete/list alternatives. The note that accepted place_action_type values vary by category is a useful caveat rather than true when-to-use guidance.

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