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

Goes well beyond the readOnly/openWorld annotations by disclosing the data-acquisition path (venue fetch vs supplied candles), caching behavior for past sessions, the reproducibility/network-free tradeoff, and the error condition for empty sessions. It stops short of describing cost, rate limits, or partial-failure behavior for malformed candles.

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?

Front-loaded with the core question and the return payload before operational caveats; no filler sentences. The inline Returns list is dense but each item is information-bearing, so it stays efficient rather than 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?

With no output schema, the description enumerates the return fields (state, direction, migration_pct, key_levels, tails, scenario_framing, invalidation), and it covers the fetch/cache/reproducibility behavior for an 8-parameter open-world tool. An agent has everything needed to call it correctly and interpret the result.

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 baseline is 3. The description's parameter claims (candles fetched from venue when omitted, session_date must be a completed session, no-candle sessions error) largely restate what the schema already documents, adding little new per-parameter meaning.

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?

Names a specific resource (Market Profile value-area migration across sessions) and frames the exact analytical question it answers (up, down, or overlapping value = directional conviction vs balance). An agent can distinguish it from generic session tools like run_session_structure without opening a 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?

Provides an explicit use-case trigger ('is value moving higher day over day?') and a hard precondition on session_date (completed UTC session, before today). It does not name alternative or overlapping sibling tools, so it falls short of full when/when-not routing.

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