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

Adds real behavioral context beyond the annotations: it discloses the possible `needs_confirmation` return, the two-pass sampling behavior, and that the call is non-persistent ('nothing is written and no feed is created'). readOnlyHint=false sits in mild tension with that claim, since it invokes an external, open-world tool, but the description is explicit about what the ledger side will not do.

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?

Four sentences, front-loaded with the operation and its non-persistence, then the workflow, then the failure mode. No sentence is filler; the warning about wrong metrics justifies its length.

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 7-parameter, nested, mutating-adjacent call with no output schema, the description covers both the invocation workflow and the shape of what comes back (a response sample plus the paths holding numbers). The only thin spot is the confirmation flow's mechanics after `needs_confirmation`, which is named but not explained.

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 86%, so the baseline is 3, but the description adds genuine meaning by explaining the role of `mapping` across the two passes ('Send no mapping for a first look... then send a mapping to confirm'). The toolArgs templating semantics are already in the schema, so this is reinforcement rather than new semantics.

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 precise verb and resource: call a connected server's tool once to see what a mapping would extract, with the explicit scope 'nothing is written and no feed is created'. It is immediately distinguishable from ledger_feeds_create, which it names by contrast.

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 an unambiguous when-to-use ('Always do this before ledger_feeds_create'), a two-phase protocol (send no mapping first, then send a mapping to confirm), and the rationale for the exclusion (an unseen mapping is how a metric fills with the wrong number).

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