update_credit_note

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

Annotations signal readOnly=false and destructiveHint=true, and the description adds substantial context beyond that: the update replaces all existing item lines, matching is by date + voucher number, the tool refuses on voucher-type collisions, and Tally's Alter lookup can silently corrupt the wrong voucher. This is exactly the kind of behavioral disclosure an agent needs.

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, each with a distinct operational purpose: what the tool does, how its field set relates to create_credit_note, how to locate the target voucher, and what happens on collision. There is no filler, and the most decision-critical information is front-loaded.

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 16-parameter mutating tool with no output schema, the description covers the essential operational context: existence check, uniqueness matching, collision failure mode, recovery step, and replacement semantics. Combined with full schema descriptions on every parameter, an agent has everything needed to invoke it correctly.

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 most parameter meaning already lives in the schema. The main description still adds value by explaining the composite matching key ('Matched by date + voucher number') and by framing the parameter set as create_credit_note's fields plus voucherNumber, which helps the agent construct valid and complete arguments.

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 ('Update'), resource ('item-invoice Credit Note in TallyPrime'), and concrete scope: replacing item lines, party, and narration. It also distinguishes the tool from create_credit_note by noting 'Same fields as create_credit_note, plus voucherNumber', so an agent can pick it apart from sibling update/create tools 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?

The description gives explicit preconditions: the credit note must exist and be uniquely matched by date + voucher number. It directly instructs the agent to call get_ledger_vouchers or get_vouchers first, and tells it what to do when a collision blocks the update — resolve in Tally first. This is clear when-to-use and how-to-proceed guidance.

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