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

Despite annotations already declaring readOnly=false and idempotent=true, the description adds substantial behavioral context: raise approval via one-time email link, immediate effect of lowering, pending_raise and raise_note in replies, spend_limits.changed notices, and rate limits (five owner emails/day, 20 changes/hour). It also discloses that this key cannot approve its own raise, a critical operational constraint.

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 dense but front-loaded, with the core purpose and field definitions first, followed by scope, approval workflow, and rate limits. It is a single long paragraph with no structural breaks, which makes it harder to scan, though nearly every sentence carries useful 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?

It describes the return value ('Returns the limits, what was spent this month and what is left') even though no output schema exists, and covers approval side effects, notification behavior, and enforcement scope. An agent has everything needed to call and interpret the result correctly.

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?

With 0% schema description coverage, the description fully compensates: it defines per_payment_usd as the most one payment can take, monthly_usd as per calendar month UTC, and low_balance_alert_usd as a notice triggered under a threshold once per top-up. It also explains whole-dollar units, that null restores defaults, and that 0 disables payments or the alert.

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 opens with a specific verb and resource — 'Set this agent key's limits for paying from its balance' — and names the three limit fields immediately. An agent can distinguish this from sibling balance and payment tools 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?

It explicitly enumerates which operations the limits cover (bounty_post with balance, bounty_fund, capability_call, settlements, etc.) and which are excluded (held results paid through a pay link, recurrences, standing policies, shared upkeep). This gives an agent clear when-to-use and when-not-to-expect-enforcement guidance.

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