Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add elevanaltd/HestAI-MCP --skill backward-compatibility-validationgit clone --depth 1 https://github.com/elevanaltd/HestAI-MCPWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/elevanaltd/hestai-mcp/backward-compatibility-validation)<a href="https://agentmods.dev/skills/elevanaltd/hestai-mcp/backward-compatibility-validation"><img src="https://agentmods.dev/badge/skills/elevanaltd/hestai-mcp/backward-compatibility-validation/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/elevanaltd/hestai-mcp/backward-compatibility-validation"><img src="https://agentmods.dev/badge/skills/elevanaltd/hestai-mcp/backward-compatibility-validation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00000 | $0.00605 |
| Opus 5 | $0.00000 | $0.00302 |
| Sonnet 5 | $0.00000 | $0.00121 |
| Haiku 4.5 | $0.00000 | $0.00060 |
Grade A, and why
backward-compatibility-validation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
===BACKWARD_COMPATIBILITY_VALIDATION=== META: TYPE::SKILL VERSION::"1.0.0" STATUS::ACTIVE PURPOSE::"Interface change impact analysis, breaking change detection, and migration path enforcement"
§1::CORE AUTHORITY::BLOCKING[breaking_changes_without_migration_path⊕undocumented_removals] SCOPE::breaking_change_detection⊕consumer_impact⊕semver_alignment⊕migration_requirements MISSION::"Prevent unintended breaking changes and ensure consumers have viable migration paths"
§2::PROTOCOL
BREAKING_CHANGE_DETECTION::[ SCHEMA::removed_fields⊕type_changes⊕nullability_changes⊕new_required_fields, API::removed_endpoints⊕renamed_paths⊕changed_HTTP_methods⊕modified_status_codes, EVENTS::removed_event_types⊕changed_payloads⊕renamed_topics, CONFIG::removed_env_vars⊕changed_defaults⊕renamed_keys, BEHAVIOR::changed_error_semantics⊕modified_ordering⊕altered_side_effects ]
CONSUMER_IMPACT_ASSESSMENT::[ 1::enumerate_known_consumers<internal⊕external>, 2::map_consumer_usage_of_changed_interface, 3::classify_impact<BREAKING⊕DEPRECATION⊕TRANSPARENT>, 4::estimate_migration_effort_per_consumer, 5::identify_consumers_unable_to_migrate_immediately ]
SEMVER_ALIGNMENT::[ BREAKING→MAJOR::removed⊕renamed⊕type_changed⊕behavior_changed, ADDITIVE→MINOR::new_optional_field⊕new_endpoint⊕new_event, FIX→PATCH::bug_correction_preserving_contract, GATE::"Version bump matches change classification?" ]
MIGRATION_PATH::[ REQUIRED_IF::breaking_change_detected, CONTENTS::[deprecation_notice_with_timeline,replacement_API_documented,migration_guide_or_script,dual_support_period_defined], NEVER::remove_without_deprecation_cycle ]
§3::GOVERNANCE
NEVER::[ approve_breaking_change_without_migration_path, skip_consumer_enumeration, allow_silent_removals<no_deprecation_notice>, mismatch_semver_with_change_type ]
ESCALATION::external_consumer_impact→technical-architect
§5::ANCHOR_KERNEL TARGET::prevent_unintended_breaking_changes_with_migration_paths NEVER::[approve_breaking_without_migration,skip_consumer_enumeration,allow_silent_removals,mismatch_semver] MUST::[detect_schema_api_event_config_behavior_changes,assess_consumer_impact,align_semver_with_classification,require_migration_path_for_breaking] GATE::"Are all breaking changes detected, consumers assessed, and migration paths defined?"
===END===
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 8d ago First seen · 62 lines · 0 tokens per session scan A f417b41cbb30
backward-compatibility-validation is a skill published in the GitHub repository elevanaltd/HestAI-MCP (0 stars, last pushed yesterday), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 605 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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