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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description still adds real value beyond that: the 3.5% processing fee is baked into the budget, the shareUrl opens the store with placements pre-loaded in the cart, and 'the plan recommends, it reserves nothing' pre-empts the wrong assumption that this creates an order.

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 sentences, front-loaded with what the tool produces before the usage condition and the output/behavior caveat. No filler, no repetition of the tool name.

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?

There is no output schema, but the description names the key return artifact (shareUrl → cart) and clarifies that nothing is reserved, which is what an agent needs to avoid mis-sequencing a follow-up create_order call. Complete for a read-only planning tool.

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 all five parameters (including count default 5, minDomainAuthority, and budget exclusiveMinimum) are already documented in the schema. The description only restates the goal/audience/budget triad and the fee-inclusive budget meaning, which the schema itself already states.

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 ('Recommend a set of publications') plus the exact inputs that drive the recommendation (goal, audience, budget). The added scope note that results are already quoted and fee-inclusive distinguishes it from a raw listing or quote tool.

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 this when a buyer says what they want to achieve and what they can spend, rather than naming publications' gives a clear when-to-use condition and an implicit when-not (the named-publication path). The sibling that handles the named-publication case (quote_placements) is not named explicitly, so the agent must infer it.

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