Add a symbol to your watchlist (writes to your account)

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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, covering the basic safety profile. The description adds useful behavioral context beyond annotations: rate limiting per key, account-level recording of each write, and the fact that adding an existing symbol leaves it in place only once.

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?

The description is front-loaded with the trigger condition, then behavior, return value, and side effects in four efficient sentences. Every sentence adds relevant information with no repetition or waste.

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 mutation tool, the definition covers the trigger, target-list fallback behavior, idempotent handling, return value, rate limits, and account auditing. With full schema coverage and helpful annotations, an agent has enough context to call it correctly without an output schema.

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 schema already documents both parameters. The description still adds fallback semantics for watchlist_id: if omitted, the symbol goes to the default list or the only list the account has, which is slightly more informative than the schema's default note.

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 uses a specific verb and resource: adding a symbol to a watchlist, with clear account-level scope. It is immediately distinguishable from sibling tools like remove_watchlist_symbol and list_watchlists without needing to inspect 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 explicitly says to call it when the user asks to watch, follow, or add a coin to their watchlist, which gives clear usage context. It does not name when not to use it or explicitly route to alternatives such as list_watchlists or remove_watchlist_symbol, so it falls short of full alternative guidance.

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