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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavior — the fee is computed and frozen at post time (2% default) — which tells the agent the cost is locked at creation. However, it never says whether the bond is active immediately or requires activate_bond, whether the principal is charged/escrowed, or what happens on a duplicate post.

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 sentences, no filler, with the core action front-loaded and the fee-freezing caveat placed where an agent will read it before calling. The only soft spot is the slightly ornamental phrase 'behind an agent's promises,' which costs a few words without adding operational meaning.

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?

An output schema exists, so return values need not be described, and the fee-freezing detail is a useful addition for a financially consequential mutation. Still, for a 5-parameter write tool with 0% schema coverage, the definition leaves too much unsaid: the role of principal_agent, currency handling, what coverage means, and the post-to-activate lifecycle.

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 must carry the burden, and it does explain the two most error-prone parameters: principal as a positive integer in minor units, and expires_at as an ISO-8601 window end. But three of five parameters — principal_agent, currency, and coverage — receive no explanation at all, leaving the agent to guess formats and defaults beyond what the bare schema titles show.

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 ('Post a surety bond') plus a scope qualifier ('behind an agent's promises'), which distinguishes it from siblings like price_bond, release_bond, and slash_bond. It stops short of explicitly naming which sibling it supersedes or follows, but the creation semantics are unambiguous.

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?

There is no when-to-use guidance and no mention of alternatives, even though the sibling list contains an obvious decision point (price_bond to quote vs. post_bond to commit) and a sequencing question (does post_bond need activate_bond afterward?). The agent must infer the workflow entirely from sibling names.

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