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

Far exceeds what annotations disclose: explains the human-gated elicitation flow, that typed values override arguments so the model cannot move a price alone, that clients without elicitation are refused, Stripe price immutability (mints a new price, old subscribers keep theirs), and that switching to one_time clears recurring price ids. This is rich, non-obvious behavioral context.

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?

Front-loaded with the core action, then layered with the gating, immutability, and cleanup consequences. Dense but each clause carries real meaning; only minor tightening possible.

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 destructive, human-gated write with no output schema, it covers the critical unknowns: override semantics, refusals, subscriber impact, side effects, and the post-write plans:sync step. Nothing an agent needs to invoke 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 0%, so the description must compensate. It clarifies the tier, amount, and billing model concepts and implies dry_run preview, but does not map fields like amount_cents vs monthly_amount_cents or explain the nested updates array, leaving some parameter 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?

States a specific verb and resource ("Change what an app's EXISTING tiers charge") plus the two changeable dimensions (amount, billing model). It implicitly distinguishes itself from siblings like update_plan_limits and update_plan_meta by naming what it does and does not touch.

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?

Explicitly says to run list_plans first for tier slugs and current amounts, and states which tiers are refused (free, contact, payg) with a reason (catalog change, not reprice). It also notes dry_run works everywhere, giving clear when/when-not guidance.

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