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

Annotations declare readOnlyHint=false and destructiveHint=false, but the description adds valuable context: it records a past decision and never executes anything. It also implies state changes without detailing duplicate handling or return values, but those are partially addressed in schema descriptions, so the bar is met.

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?

Two sentences, front-loaded with the essential action, and zero filler. Every word earns its place, and the structure cleanly follows action, purpose, and constraints.

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?

The description fully explains the tool's primary purpose and boundaries for a 10-parameter tool with no output schema. It doesn't mention return details or duplicate confirmation behavior, but the schema's parameter descriptions cover the latter, so the setup is sufficiently complete.

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 input schema already provides thorough meaning for all 10 parameters. The description restates some fields but adds little beyond mapping 'how you felt' to emotional_state. Baseline 3 is appropriate because the schema carries the load.

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 ('Log') and resource ('Trading Journal'), enumerates the key fields (ticker, direction, entry date, price, quantity), and disambiguates from siblings by stating it records past decisions. This clearly differentiates it from update_trade, close_trade, delete_trade, and import_trades.

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 provides clear context for when to use the tool ('a trade you've already made', 'never executes anything') and restricts scope to 'Stocks, ETFs, and crypto only.' It does not explicitly name alternative tools for different actions, but the context is sufficient to guide selection.

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