upsert_crypto_synced_balance_history

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

The annotations only provide idempotentHint, so the description adds meaningful behavior: all-or-nothing semantics, the requirement that months be past calendar months, and the cross-field constraint that an entry-level symbol must match the symbol argument. These go beyond what annotations alone convey.

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: the first states the purpose, and the next two state essential constraints. There is no filler, repetition of obvious details, or bloated context. Every sentence earns its place.

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?

Given the comprehensive schema, idempotentHint annotation, and the description's atomicity and month constraints, an agent has enough to call this tool correctly. The main gaps are the lack of explicit sibling routing and no mention of return behavior, but neither is essential for correct invocation.

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 the schema already documents each parameter well. The description adds value by stating a non-obvious cross-parameter invariant: if an entry sets symbol, it must match the top-level symbol argument. This is not fully expressed in the schema.

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 starts with a precise action: 'Create or update monthly balance history entries for a synced crypto holding.' This clearly names the verb, resource, and scope, and distinguishes it from sibling tools like get_crypto_synced_balance_history or generic account balance upserts.

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?

Usage is implied by the description: this is for synced crypto balance history mutation. However, it never explicitly says when to use this instead of related tools such as upsert_account_balance_history or get_crypto_synced_balance_history, and it provides no exclusions or alternative routing.

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