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

Annotations already declare readOnlyHint=true and idempotentHint=true, so safety is covered. The description adds behavioral warnings (don't assume organization) and a confirmation requirement, which are important for correct agent behavior. No contradictions with annotations.

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?

The description is concise, with the main purpose in the first sentence, followed by two key behavioral notes, and a brief bulk-support statement. Every sentence adds value; no filler or repetition.

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 simple read-only tool with good annotations, the description is sufficiently complete: it states what the tool does, provides a crucial warning, and includes bulk execution. No output schema exists, but the return value (cost) is straightforward. Could have mentioned error conditions, but not required given the simplicity.

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 0%, so the description carries the burden. It implicitly covers 'type' by mentioning project/branch, and organization_id via the warning about organization variability. It mentions 'organization_ids' for bulk. However, it doesn't explicitly state that package_id is required or explain the relationship between organization_id and organization_ids, leaving some ambiguity.

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 clearly states the tool 'Gets the cost of creating a new project or branch.' It uses a specific verb ('Gets') and resource ('cost'), and distinguishes itself from sibling tools like supabase_create_project and supabase_confirm_cost by focusing on cost retrieval. The scope is explicit.

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?

The description provides clear usage context: never assume the organization (costs vary by org) and to repeat the cost and confirm understanding before proceeding. It also mentions bulk support. It doesn't explicitly name alternatives or when not to use, but the guidance is sufficient for the typical workflow.

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