Analyze a Pokémon card image

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the description doesn't need to repeat safety. Instead it adds rich behavioral context: it only matches 'supported marketplace variants', it inspects specific card features, it 'obey[s] the returned answer_policy'. The one gap is it doesn't disclose rate limits or what happens with unsupported cards, but given the annotations cover the safety profile, this is strong.

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 purpose in the first sentence and then efficiently layers scope and constraints. It's moderately long but every sentence adds functional information (handling rotated photos, printing identification, marketplace matching, answer_policy obedience). Slightly verbose with 'UNIVERSAL HIGH-LEVEL ENTRY POINT' shouting, but structurally sound and not padded.

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 high-complexity entry-point tool with 6 parameters, 0% schema coverage, and an output schema present, the description covers the core behavioral contract well: input format, preprocessing tolerance, what it inspects, what it won't do. The output schema presumably documents return shape, so that doesn't need repeating. Minor gaps: doesn't explain top_k or visual_verify semantics, but the overall description is substantially complete for agent dispatch.

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 0%, but the description compensates meaningfully by explaining the key parameter semantics: it tells users to pass the attachment 'as a real local path or base64' (mapping to image_path and image_base64), and mentions the language hint concept. It doesn't document top_k, visual_verify, or user_request individually, but the tool's purpose statement inherently clarifies the user_request and boolean flags are reasonable defaults. With 0% schema coverage, the description carries the burden but doesn't fully cover all 6 parameters, hence a 4 rather than 5.

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 this is the 'UNIVERSAL HIGH-LEVEL ENTRY POINT' for natural-language questions about Pokémon TCG card photos, with explicit examples ('what is this card?', 'what is this worth?'). It names specific verb+resource (analyze a card image) and distinguishes itself from siblings (identify_card_from_image, search_cards, get_card_prices) by positioning itself as the router that precedes those tools.

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 when-to-use guidance ('Call this before generic vision, catalog search, pricing tools, or web search') and what-it-handles constraints (screenshots, rotated/upside-down/skewed photos, edition stamps, promos, errors, holo patterns). It also gives clear negative guidance: 'never add outside prices, grading, authentication, or sold listings.' This is exemplary usage direction with both positive triggers and exclusions.

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