update_portfolio

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

Annotations only provide destructiveHint=true, but the description substantially enriches behavioral understanding: partial update semantics, auto-expansion of asset universe, restriction on removing assets, and persistence of options_positions. This goes far beyond the annotation and clearly explains what mutations occur.

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 longer than average but every sentence earns its place. It is front-loaded with the core purpose, followed by field semantics, then a clearly labeled ASSET MUTATION section covering edge cases. No fluff or repetition; density is appropriate for the tool's complexity.

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 an output schema, the description covers all important usage contexts: how to add assets, how to zero out positions, when to use add_feature, and the role of options_positions. It connects to sibling tools and provides a complete picture for an agent to invoke it correctly.

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 baseline is 3, but the description adds critical semantics: omitted fields stay unchanged, weights must sum to 1.0, ticker auto-expansion logic, and the purpose of options_positions for analyze_derivatives. This adds meaning beyond the schema field descriptions.

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 clearly states the tool's function: 'Update an existing portfolio. Can change name, description, weights, capital, and/or options_positions.' This is a specific verb+resource with explicit scope. It distinguishes from create/delete siblings by emphasizing 'existing' and later contrasting with create_portfolio_from_assets for removing assets.

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?

Provides explicit guidance on when to use alternatives: 'If the ticker isn't in the catalog yet, call add_feature first' and 'only create_portfolio_from_assets can produce a portfolio with a strictly smaller asset universe.' Also clarifies partial update usage: 'Only pass the fields you want to update — omitted fields stay unchanged.' This is exemplary guidance.

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