update_material_in

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

Beyond the annotations (destructiveHint=true, idempotentHint=true), the description adds precisely what gets destroyed ('replacing its item lines and narration'), the matching key ('Matched by date + voucher number'), and a critical failure mode: 'Refuses if another voucher type shares the same number on that date (confirmed live: Tally's Alter lookup ignores voucher type and can silently corrupt the wrong one).' The collision-refusal behavior and remediation guidance ('resolve the collision in Tally first') are exactly the high-value context the rubric rewards.

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 earning its place: purpose and scope first, then schema-reuse note, then matching/precondition guidance, then the critical warning with evidence. The structure is logical and front-loaded, with zero filler; even the longest sentence carries essential safety information.

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?

Despite having no output schema, the description gives an agent everything needed to call correctly: what the operation does and replaces, the identity key, the prerequisite lookup steps, and the collision failure mode with remediation. With annotations already covering the destructive/idempotent safety profile, nothing material is missing for a mutation 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 adds value beyond the schema by explaining that date and voucherNumber form the identity key ('Matched by date + voucher number') and by flagging voucherNumber as the parameter that carries collision risk. It also avoids duplicating per-field docs by pointing to create_material_in for shared field 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?

The description opens with a precise verb+resource+scope: 'Update an existing Material In voucher in TallyPrime, replacing its item lines and narration.' It clearly differentiates from create_material_in (create vs. update), update_material_out (different voucher type), and update_voucher (generic updater) without needing to open any 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: 'use get_ledger_vouchers or get_vouchers first to confirm it exists and is unique,' and references create_material_in by noting 'Same fields as create_material_in, plus voucherNumber.' It does not explicitly name when-not-to-use alternatives such as update_material_out or update_voucher, and it doesn't state 'use create_material_in if the voucher doesn't exist,' so it falls just short of exhaustive routing guidance.

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