fixed-income

Check a bond valuation for consistency

check_consistency_tool

Audit a claimed bond yield against required bounds: below par yields must exceed coupon and current yield; above par reverses. Returns the correct yield to show error size.

Instructions

Test a yield someone has already produced against the required bounds.

Use this to audit a figure rather than compute one — for example when checking work, or when a yield appears in a document and its plausibility matters.

A bond priced below par must yield more than its coupon and more than its current yield; above par, the ordering reverses. These bounds need no iteration and reject a whole class of wrong answers immediately. The correctly solved yield is returned too, so the size of any error is visible.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`day_count`	No	Day-count convention used for accrual. ACT/ACT ICMA is the standard for most government and corporate bonds.	ACT/ACT ICMA
`face_value`	Yes	Redemption amount in currency units, e.g. 1000.
`issue_date`	Yes	Issue (dated) date in ISO format, e.g. 2024-03-15.
`maturity_date`	Yes	Redemption date in ISO format, e.g. 2029-03-15.
`claimed_ytm_pct`	Yes	The yield to audit, as a percentage. This is the figure to be tested, not one to compute.
`coupon_rate_pct`	Yes	Annual coupon rate as a PERCENTAGE. Pass 4.0 for a 4% coupon, not 0.04. Zero for a zero-coupon bond.
`settlement_date`	Yes	Valuation date in ISO format. Must fall between issue and maturity, e.g. 2025-09-11.
`payments_per_year`	Yes	Coupon payments per year: 1 annual, 2 semi-annual, 4 quarterly, 12 monthly. Most government bonds pay semi-annually.
`clean_price_pct_of_face`	Yes	Quoted clean price as a PERCENTAGE OF FACE, excluding accrued interest. Pass 97.80 for a bond quoted at 97.80%. This is not a currency amount.

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.2Sep 16, 2026

TDQS

A4.3/5.0

Behavior4/5

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It explains the bound-checking logic (below par yields exceed coupon and current yield; above par reversed) and states that the correctly solved yield is returned so error size is visible. This gives meaningful insight beyond the schema without being exhaustive, but no limitations or edge cases are mentioned.

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 concise—four sentences—with the core purpose front-loaded in the first sentence. Every sentence adds value: purpose, usage context, the mathematical bound logic, and the return behavior. There is no fluff or redundancy.

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?

Given the output schema exists, return values need not be explained. The description covers the core behavior, use case, and even the underlying logic that an agent might need to trust the results. For a tool with 9 parameters but full schema coverage, the description is sufficient for correct invocation and interpretation.

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

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so all parameters are already well-documented in the schema. The description adds no parameter-specific detail beyond that, which is acceptable at the baseline. It does reinforce that claimed_ytm_pct is the figure to test, but that is already in the schema. No compensation needed.

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?

The description opens with a specific verb and resource: 'Test a yield someone has already produced against the required bounds.' It explicitly contrasts with computation tools ('audit a figure rather than compute one'), distinguishing it from siblings like yield_from_price_tool and price_from_yield_tool. The purpose is unambiguous and well-differentiated.

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

Usage Guidelines4/5

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

It states when to use ('when checking work, or when a yield appears in a document and its plausibility matters') and implicitly when not to ('rather than compute one'). However, it does not name specific alternative tools, so while the context is clear, it lacks explicit alternatives. This fits the 'clear context, no exclusions' level.

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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