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

Annotations already cover the read-only/idempotent/non-destructive profile, and the description adds genuine context beyond that: receipting at mcp.rco-records.ai with the door as writer, both manufacturer-side and node signatures returned, and a soft not_found status instead of an error. These are non-obvious behaviors an agent could not derive from annotations or schema.

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 resource and its scope in the first clause, and the not_found contract is cleanly separated into a second sentence. The single long sentence is dense and carries some opaque internal jargon ('the door as writer'), but nothing is redundant.

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 does the necessary work of describing the return (the statement, both signatures, not_found status) and the side effect (receipting). It leaves the shape/format of the returned statement unspecified, a modest gap for a 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?

Schema coverage is 100%, so the baseline is 3; the description earns an extra point by tying the three parameters into a coherent mutually-exclusive selection model (current vs explicit version vs last-filed-at-or-before as_of). It adds little on the subject/ISIN format, which the schema already documents.

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 manufacturer's target market statement for an ISIN) with its home-node location, and the version-selection semantics clearly separate it from write/verify siblings. It stops short of naming siblings such as verify_target_market or list_target_market_versions, so the routing is inferred rather than spelled out.

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?

Use context is clear: fetch the current, a specific, or an as-of version of a statement, with the no-statement case explicitly answered as status not_found rather than an error. No exclusion or alternative-tool routing is given, so an agent must infer that file_target_market is the write path.

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