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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds real value beyond that by disclosing that verification recomputes hash chains (implying compute cost) and that it "returns the actual verifier verdict, including failures" — i.e. failures are surfaced, not swallowed. It stops short of stating latency, cost, or what happens when signatures/anchors are disabled.

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?

Two sentences, zero filler, with the mechanism stated first and the scope caveat last. Every clause earns its place by either defining the operation or bounding its interpretation.

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 one-parameter, annotation-rich tool with no output schema, the description covers what is checked, that failures are reported honestly, and what class of answer is out of scope. The remaining gap is the shape of the verdict (fields, pass/fail granularity per signature or anchor), which an agent would have to discover by calling it.

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 one parameter and 100% schema coverage including a default, the schema already carries the meaning; the description only echoes "ledger stream." It adds no detail on valid stream names, whether the default stream is the common case, or what an unknown stream does — the baseline 3 applies.

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?

"Verify a ledger stream by recomputing hash-chain commitments and checking enabled signatures and anchors" names a specific verb, a specific resource, and the exact mechanism used. The closing clause "Verifies record integrity, not economic accuracy" separates it cleanly from the economic and board-style siblings in the same namespace.

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?

The boundary "record integrity, not economic accuracy" gives a genuine when-not signal that steers agents away from using this for analysis questions. However, no sibling is named as the alternative for the economic side, so the agent must still infer routing from the wider tool list.

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