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

With no annotations, the description carries the full burden and does so: it discloses BER normalization behavior, per-algorithm padding reconstruction (PSS params, RSA PKCS#1 v1.5, ECDSA, Ed25519, SHA1), and the non-obvious failure semantics that verification failure returns verified=false + reason rather than an error code. It also flags that chain warnings are advisory, not failures.

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 purpose and organized under clear 【算法】【参数】【输出】【注意】 headings, so it is scannable despite its length. It is dense but each section carries information an agent needs; there is mild overlap with the schema descriptions, which keeps it just short of a 5.

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?

There is no output schema, so the description must enumerate returns, and it does (verified, reason, key_source, detached, content_in_hex, content_matches, algorithm OIDs, ber_features, structure_tree). Combined with algorithm coverage, failure semantics, and the cert_verify boundary, nothing an agent needs to call this correctly is missing.

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%, so the baseline is 3, but the description adds real meaning beyond it: the ≤16MB bound, the attached-vs-detached rule that makes data_in_hex conditionally required despite the schema marking nothing required, and the sid-based fallback for the certificate parameter.

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 (验签/verify) and resource (CMS SignedData, RFC 5652 §5) with a scope note that BER/DER inputs are both tolerated. It also draws an explicit boundary against the sibling cert_verify (chain validity is out of scope), so an agent can tell it apart from cms_signed_sign and cose_sign1_verify without opening the schema.

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 conditional guidance: detached messages require data_in_hex, attached messages use the embedded eContent and ignore the field, and empty signer_certificate_in_pem triggers lookup from the certificates set by sid. It also names cert_verify as the owner of chain validity. No explicit exclusion of the signing sibling, but the context is unambiguous.

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