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

Annotations already cover the read-only, idempotent, closed-world safety profile, and the description adds substantial context beyond them: required Last Price credential, credential-scoping rules (own agent only vs any agent in workspace), and the concrete 403 failure mode for unclaimed sandbox workspaces. This is exactly the kind of preconditions an agent needs before calling.

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?

Four compact sentences, each front-loaded around purpose, usage, and access preconditions, with no filler. There is mild redundancy between the credential-scoping sentence and the schema's agent_id description.

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?

With no output schema, the description compensates by enumerating the return contents (scopes plus descriptions, pending approvals, rate limit, idempotency keys), and it covers all preconditions for a one-parameter read tool. Nothing an agent needs to call 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 100% and the single parameter's own description already states that an own credential may name only its own agent; the description's 'Pass agent_id' and credential note largely restate that. Baseline 3 is appropriate since the schema carries the parameter meaning.

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 ('Read what one agent may do') and enumerates exactly what is returned: effective scopes with descriptions, pending approval count, rate limit, and idempotency key behavior. An agent can distinguish this from neighboring tools like check_agent_readiness or get_agent_value_receipt 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?

Gives an explicit usage trigger ('Call it before a planned action ... instead of meeting a 403') and defines the access conditions under which it may be called (own credential vs workspace credential, Last Price credential, claimed workspace). It does not name alternate tools for overlapping checks, so it stops short of a full when-not/alternatives statement.

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