FirmTape - SPX dealer positioning

Gamma by strike

get_gex_profile

Read-onlyIdempotent

The SPX dealer gamma LADDER for one minute of a finished session: gamma by strike around spot, the level set, and the heaviest strikes. Readable as the MEASURED book (signed off the trade tape, FirmTape's own read), as the OPEN_INTEREST convention every other public GEX chart draws, or as the VOLUME convention — the same minute through three lenses. Use when: the question is about SHAPE — where gamma sits, how heavy a wall is, how far the three conventions disagree — or about one moment inside a session rather than the day as a whole. Not for: a day's headline numbers (get_session), the level set alone (get_levels), or movement across days (get_level_history). Limits: finished sessions only, one frame every 5 minutes (a requested minute snaps back to the frame at or before it), published window ±2.5% of spot; the three books are not comparable in magnitude. Measurements only, no buy/sell signals.

Input Schema

TableJSON Schema

Name	Required	Description
`day`	Yes	A finished trading day, YYYY-MM-DD. Call list_sessions if unsure which days exist.
`book`	No	Which book to read (default measured). open_interest is the convention rival tools print.
`minute`	No	ET minute HH:MM inside 09:30-16:00. Snaps back to the frame at or before it, so quote the minute the answer returns. Default: the last frame of the session.
`expiry_scope`	No	all = every expiry the session's book was pulled with (default); 0dte = the same-day slice alone
`strikes_around_spot`	No	How many strikes to return each side of spot (default 20). Raise it for the whole published window, which is +/-2.5% of spot.

Output Schema

TableJSON Schema

Name	Required	Description
`day`	Yes	Trading day, YYYY-MM-DD
`book`	Yes	Which book was read: measured, open_interest or volume
`spot`	Yes	SPX at that minute
`unit`	Yes	Unit of every gamma number below
`levels`	Yes	Dealer-positioning levels in SPX index points; null when the session did not produce one
`minute`	Yes	The ET minute (HH:MM) this profile actually belongs to. The archive keeps a frame every 5 minutes, so a requested minute snaps back to the frame at or before it — quote the minute returned here, not the one asked for.
`replay`	Yes	Free minute-by-minute replay of the session on FirmTape
`strikes`	Yes	Dealer gamma by strike at that minute, lowest strike first
`summary`	Yes	One sentence carrying this answer's numbers, its trading day and its source, written to be quoted verbatim to a reader rather than paraphrased.
`heaviest`	Yes	The largest strikes by absolute gamma inside the window, heaviest first
`book_note`	No	How this book is built, and what it can and cannot be compared with
`expiry_scope`	Yes	all = every expiry this session's book was pulled with; 0dte = the same-day slice alone
`strikes_returned`	Yes	How many strikes the window actually held
`net_gamma_in_window`	Yes	Sum of the returned strikes — a window total, not the session's net gamma

TDQS

A4.9/5.0

Behavior5/5

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

Annotations already establish read-only, idempotent, non-destructive behavior, so the bar is lower, but the description still adds substantial context: finished sessions only, 5-minute frame snapping, ±2.5% published window, non-comparable book magnitudes, and no buy/sell signals. This tells the agent what to expect beyond what annotations convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is long but tightly organized: definition, conventions, use-when, not-for, limits, and a final qualifier. Every sentence carries operational or routing information, and the core purpose is front-loaded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with a rich output schema and full parameter documentation, the description supplies all the missing operational context: conventions, minute snapping, session restrictions, window limits, and exclusions. An agent has enough to select the tool, choose parameters, and interpret the result correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

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, but the description enriches parameter meaning by explaining that the three book conventions offer three lenses on the same minute, that books are not comparable in magnitude, and that the published window constrains strikes_around_spot. This goes beyond ordinary schema documentation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: it returns the SPX dealer gamma ladder for a single minute of a finished session, including gamma by strike, the level set, and heaviest strikes. It also distinguishes itself from siblings by naming what it is not for, so an agent can recognize it as the minute-level shape tool.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says 'Use when' the question is about gamma shape or a single moment in a session, and 'Not for' day headline numbers, level set alone, or cross-day movement, naming get_session, get_levels, and get_level_history as alternatives. This gives the agent precise routing guidance.

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

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TDQS

A4.6/5.0

Disambiguation5/5

Every tool targets a distinct resource and granularity: documents (search/fetch), session enumeration (list_sessions), day-level measurements (get_session/get_levels), intraday shape (get_gex_profile), multi-day trends (get_level_history), and strategy backtesting (options_strategy_test). The descriptions go further than usual, using explicit 'Not for' cross-references so even get_levels vs get_session — a deliberate strict subset — reads unambiguously.

Naming Consistency4/5

The measurement tools follow a clean get_<nouon> convention (get_session, get_levels, get_level_history, get_gex_profile) and list_sessions fits the verb_nouon pattern. fetch and search are bare single-word verbs that break the pattern slightly — fetch_document / search_documents would be more uniform — and options_strategy_test is a compressed compound, but the overall snake_case style and semantic grouping are predictable.

Tool Count5/5

Eight tools is well within the 3-15 sweet spot for a specialized data server. Each tool carries a clearly differentiated job: two document access, one enumeration, four measurement surfaces (single-day full, single-day levels, intraday ladder, multi-day history), and one analysis operation. Nothing feels like filler and nothing essential is missing.

Completeness4/5

The domain is well covered: session discovery (list_sessions), document retrieval (search/fetch), full daily readings (get_session), subset views (get_levels), intraday gamma shape (get_gex_profile), and cross-day movement (get_level_history) — plus a strategy tester. Minor gaps exist, such as no way to compare gamma-ladder shape across multiple days without repeated get_gex_profile calls, but no workflow dead-ends for the stated purpose.

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