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

With no annotations, the description carries the full burden and discharges much of it: it discloses the credential required ('key'), the cost ('Free; counts against the notarise allowance'), and non-obvious semantics ('The record is attached to your earliest entry for that fingerprint; the lodgement time the receipt attests does not change'). It does not cover failure/abort behavior or limits on part count/size, so it is strong but not exhaustive.

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 dense but front-loaded: purpose first, then workflow, then behavioral caveats, then credential/cost/source. Nearly every clause carries information an agent needs; the PD8 citations and 'v1.3' provenance are the closest thing to filler, slightly blunting conciseness.

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 two-parameter tool with a nested object, no output schema, and no annotations, the description supplies the missing scaffolding: it states what is returned ('get an upload id') and the full multi-call protocol to complete the upload. It leaves some ambiguity about the parts' size/count rules, but the essentials are present.

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 50%, and the description compensates by explaining the structured object's key ordering rule ('envelopeSha256 is the hash of those hashes joined by newlines') and the provenance of `sha256` ('a fingerprint you already lodged'). Several nested fields (wrappedOperator, operatorKeyId, plaintextHmac, bytes) are left to the schema, which reduces the score below a full 5.

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 opens with a specific verb and resource ('Opens a chunked upload of a sealed envelope against a fingerprint you already lodged') and states the triggering condition ('sealed record is too large to send in one lodgement'). It implicitly distinguishes itself from put_held_upload_part and complete_held_upload by naming the exact endpoints each handles, so an agent can tell them apart.

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?

It gives clear context for when this tool applies (payload too large for a single lodgement) and lays out the follow-on steps (PUT parts, POST complete). It does not explicitly frame the sibling tools as alternatives or state when-not to use this tool, so it falls short of a full routing instruction.

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