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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the description's added context is what counts: it discloses that the policy is immutable and that changing presets requires a new sandbox. It also tells the agent the return is raw YAML text rather than a parsed object, which affects how it should be presented.

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 short sentences, front-loaded with what is returned, then when to use it, then the immutability constraint. No filler or restated name/title.

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?

No output schema exists, so the description compensates by describing the returned document's contents. Combined with the immutability note and clear usage triggers, an agent has everything needed to call this correctly and interpret the result.

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?

Only one parameter, and its schema coverage is 100% with a description pointing to sandbox_create for the ID. The tool description adds nothing about the sandbox_id itself, but the schema already carries that burden, so a baseline 3 is appropriate.

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 (returns the sandbox's spendctl.yaml as text) and enumerates the contents the caller will see: preset name, budgets, allowed hosts, approval rules. This clearly separates it from siblings like check_budget or list_receipts, which report runtime state rather than the policy document.

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?

Gives explicit use cases: explain why a payment was refused or held, or inspect what a spendctl policy file looks like. It also steers the caller away from trying to mutate the policy ('create a sandbox with another preset instead'), though it does not name the sibling tool sandbox_create explicitly.

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