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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that: it discloses that the manifest records a recomputed event hash chain and how it is signed, that a download path is returned, and that the call is free. The 'read-only' clause is redundant with the annotation, keeping it off a 5.

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?

It is a dense, comma-heavy sentence, but the return contents are front-loaded and each clause (file inventory, hash chain, signing, download path, access mode) carries distinct information. Slightly over-stuffed, but no sentence is wasted.

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 must carry the return contract, and it does: it enumerates the manifest's contents, the hash-chain recomputation, the signing record, and the download path. An agent has enough to know what comes back and what the artifact is for.

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 100% and the single run_id parameter is documented as 'A run id from rig.run.create.' The description adds no syntax, format, or sourcing detail beyond the schema, so the baseline of 3 for a fully-covered single parameter 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?

The description names the resource precisely ('the manifest of a run's evidence bundle') and enumerates what the manifest contains — the run, counts, files with sizes and SHA-256, hash chain, signature, download path. It is clearly a read of a specific artifact, not a generic list. It doesn't distinguish itself from the sibling rig.evidence.receipt, so it stops short of a 5.

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 only contextual cue is that the bundle 'is a ZIP for a person or a CI step to fetch with the CLI or a platform key', which hints at audience but not tool selection. There is no guidance on when to call this instead of rig.evidence.receipt, rig.run.get, or rig.event.list, nor any prerequisite or exclusion.

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