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

The description discloses a concrete operational trait not present in annotations: a fixed $0.20 charge per call, which matters for a non-readOnly, non-idempotent tool an agent may call repeatedly. Annotations already cover the safety profile (destructiveHint=false, openWorldHint=false), so the remaining gaps — no description of the returned structure or of what happens on repeat calls — are tolerable at this level.

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?

Three short sentences with no filler, and the core action is front-loaded. The final fragment, "Getting transactions ready for bookkeeping," is the weakest line — it restates intent vaguely rather than adding routing information — but it is brief enough not to hurt.

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 two-parameter, no-output-schema tool, the description should say roughly what comes back (e.g. the original lines annotated with a category, and what happens to uncategorisable lines). It covers cost and rough intent but leaves the return shape and the optional categories parameter's behaviour undocumented, so an agent must infer the result.

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% and both parameters (document, categories) are documented in the schema itself, so the baseline of 3 applies. The description adds nothing about parameter format, e.g. whether categories is comma-separated or free text, or how the model behaves when categories is omitted.

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 first sentence gives a specific verb and resource: assign a category to each expense line. That is enough to separate it from extraction siblings like fikra_extract_invoice or fikra_process_receipt, but the description never names those siblings or states the boundary explicitly, so differentiation is inferred rather than stated.

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?

"Getting transactions ready for bookkeeping" implies a workflow stage (post-extraction, pre-reporting), which is useful implied context. However there is no explicit statement of when to choose this versus fikra_process_receipt, fikra_generate_expense_report, or fikra_reconcile_invoice_receipt, and no prerequisites are given.

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