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

Annotations already declare readOnlyHint=true; the description adds real context beyond that — no auth needed, the call is repeatable/idempotent, and the sealing-interval constraint on the returned digest. It also notes post-sealing behavior (reports whether the prefix still matches).

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?

Front-loaded with the core action and kept to four sentences, though the closing 'No auth needed. READ-ONLY: this call changes nothing and can be repeated safely' partially restates the readOnlyHint annotation, which is mild redundancy.

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 carries the return burden and does so: it explains the reader gets the verbatim prefix rows plus the seal-over digest, and what is reported after sealing. Complete for a zero-parameter read tool.

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?

The tool takes zero parameters, so there is nothing for the description to document; the baseline of 4 applies. No parameter-related content is missing.

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 ('Read') and resource ('the legacy prefix of each public chain ... verbatim, with the digest a manifest row would seal over them') with enough scope detail to be unambiguous. It contrasts its pre-sealing role against sealing without explicitly naming the sibling legacy_manifest_seal.

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 clear workflow context: this is the 'pre-publication surface' and the caller should record the digest off-machine before sealing because a manifest needs a digest public for the full interval. No explicit when-not or named alternative, but the usage condition is well conveyed.

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