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

Annotations provide readOnlyHint=true, and the description adds meaningful behavioral context: it returns both full combos and near-misses, includes card prices for near-misses, and filters suggestions based on format/commander legality. It does not contradict annotations and goes beyond them by explaining the curated database source and integration with rate_deck.

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 two sentences, front-loaded with the core function, and each clause earns its place by adding critical information about features, inputs, and usage. It is compact yet information-dense without fluff.

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 output schema exists, so return values need not be described. The description covers purpose, key behavior (full combos + near-misses), input requirements (format/commander), and integration with rate_deck. Given the tool's moderate complexity, this is fully complete 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 0%, so description must compensate. It explains the purpose of `format` and `commander` for near-miss filtering, but does not describe the required `cards` parameter or the optional `limit`. This partial coverage is useful but leaves significant gaps for the two unnamed parameters.

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 detects known combos in a decklist using Commander Spellbook's curated database. It distinguishes itself from siblings like find_synergies by specifying 'known combos' and 'near-misses one card away', giving a precise verb+resource+scope.

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?

Explicitly instructs to pass `format` and `commander` for filtering near-misses, and tells when to use this tool: 'instead of recalling combos from memory' and 'also feeds rate_deck's compact-combo check'. This clearly sets context and differentiates from alternatives.

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